diff --git a/Assignment.cpp b/Assignment.cpp
new file mode 100644
index 0000000..990a80a
--- /dev/null
+++ b/Assignment.cpp
@@ -0,0 +1,40 @@
+#include "Assignment.h"
+#include "FormatError.h"
+
+using err::FormatError;
+
+namespace models {
+    Assignment::Assignment(const int& user_id, const int& task_id) : user_id(user_id), task_id(task_id) {}
+    Assignment::Assignment(): user_id(0), task_id(0) {}
+
+    ostream& Assignment::write(ostream& stream) {
+        stream << this;
+        return stream;
+    }
+
+    int Assignment::get_task_id() const {
+        return this->task_id;
+    }
+
+    int Assignment::get_user_id() const {
+        return this->user_id;
+    }
+
+    ostream& operator<<(ostream& os, const Assignment& t) {
+        os << t.get_user_id() << " " << t.get_task_id();
+        return os;
+    }
+
+    istream& operator>>(istream& is, Assignment& t) {
+        int user_id;
+        is >> user_id;
+        if (!is)
+            throw FormatError("Userid Nan");
+        int task_id;
+        is >> task_id;
+        if (!is)
+            throw FormatError("Taskid Nan");
+        t = {user_id, task_id};
+        return is;
+    }
+}
diff --git a/Assignment.h b/Assignment.h
new file mode 100644
index 0000000..69f0f76
--- /dev/null
+++ b/Assignment.h
@@ -0,0 +1,27 @@
+#include "std_lib_inc.h"
+#ifndef ASSIGNMENT_H
+#define ASSIGNMENT_H
+
+namespace models {
+    class Assignment {
+        private:
+            int user_id;
+            int task_id;
+        public:
+            Assignment(const int& user_id, const int& task_id);
+            Assignment();
+            ostream& write(ostream& stream);
+
+            int get_user_id() const;
+            int get_task_id() const;
+
+            friend ostream& operator<<(ostream& os, const Assignment& t);
+            friend istream& operator>>(istream& is, Assignment& t);
+    };
+
+    ostream& operator<<(ostream& os, const Assignment& t);
+    istream& operator>>(istream& is, Assignment& t);
+}
+
+#endif // ASSIGNMENT_H
+
diff --git a/DataType.h b/DataType.h
new file mode 100644
index 0000000..40b8667
--- /dev/null
+++ b/DataType.h
@@ -0,0 +1,15 @@
+#include "std_lib_inc.h"
+#ifndef READINSTATUS_H
+#define READINSTATUS_H
+
+namespace util {
+    enum class DataType {
+        INIT,
+        USER,
+        TASK,
+        USERTASKINDEX
+    };
+}
+
+#endif // READINSTATUS_H
+
diff --git a/FileError.h b/FileError.h
new file mode 100644
index 0000000..4505ff9
--- /dev/null
+++ b/FileError.h
@@ -0,0 +1,20 @@
+#include "std_lib_inc.h"
+#include <exception>
+#ifndef FILEERROR_H
+#define FILEERROR_H
+
+namespace err {
+    class FileError : public exception {
+        private:
+            string what;
+
+        public:
+            FileError(const string& msg) : exception(), what(msg) {}
+            string why() {
+                return this->what;
+            }
+    };
+}
+
+#endif // FILEERROR_H
+
diff --git a/FormatError.h b/FormatError.h
new file mode 100644
index 0000000..95078cc
--- /dev/null
+++ b/FormatError.h
@@ -0,0 +1,20 @@
+#include "std_lib_inc.h"
+#include <exception>
+#ifndef FORMATERROR_H
+#define FORMATERROR_H
+
+namespace err {
+    class FormatError : public exception {
+        private:
+            string what;
+
+        public:
+            FormatError(const string& msg) : exception(), what(msg) {}
+            string why() {
+                return this->what;
+            }
+    };
+}
+
+#endif // FORMATERROR_H
+
diff --git a/Manager.cpp b/Manager.cpp
new file mode 100644
index 0000000..458a3ed
--- /dev/null
+++ b/Manager.cpp
@@ -0,0 +1,107 @@
+#include "Manager.h"
+#include "FileError.h"
+#include <fstream>
+
+using err::FileError;
+using util::DataType;
+
+namespace util {
+    Manager::Manager(): users({}), tasks({}), user_task_index({}), filename("tasks") {
+        ifstream in (this->filename);
+        if (!in)
+        {
+            // throw FileError("Could not open file input stream!");
+            this->save();
+            in.clear();
+            in.open(this->filename);
+            if (!in)
+                throw FileError("Could not open file input stream!");
+        }
+        DataType current_type = DataType::INIT;
+        string d;
+        char c;
+        while(true) {
+            in >> c;
+            if (in.eof() || c == EOF)
+                break;
+            if (c == '\n')
+            {
+                in >> d;
+                continue;
+            }
+            if (c == '['){
+                switch (current_type)
+                {
+                case DataType::INIT:
+                    current_type = DataType::TASK;
+                    break;
+                case DataType::TASK:
+                    current_type = DataType::USER;
+                    break;
+                case DataType::USER:
+                    current_type = DataType::USERTASKINDEX;
+                    break;
+                case DataType::USERTASKINDEX:
+                    break; // This should not happen. There is nothing after [assignments]
+                }
+                in >> d;
+                continue;
+            }
+            in.putback(c);
+            switch (current_type) {
+            case DataType::INIT:
+                break;
+                case DataType::TASK:
+                    {
+                        Task t;
+                        in >> t;
+                        this->tasks.push_back(t);
+                    }
+                    break;
+                case DataType::USER:
+                    {
+                        User u;
+                        in >> u;
+                        this->users.push_back(u);
+                    }
+                    break;
+                case DataType::USERTASKINDEX:
+                    {
+                        Assignment a;
+                        in >> a;
+                        this->user_task_index.push_back(a);
+                    }
+                    break;
+            }
+        }
+        in.close();
+    }
+
+    void Manager::save() {
+        ofstream out = ofstream(this->filename);
+        if (!out)
+            throw FileError("Could not open file output stream!");
+        out << "[tasks]\n";
+        for (Task& t : this->tasks)
+            t.write(out);
+        out << "\n[users]\n";
+        for (User& u : this->users)
+            u.write(out);
+        out << "\n[assignments]\n";
+        for (Assignment& uti: this->user_task_index)
+            uti.write(out);
+        out.close();
+    }
+
+    vector<User> Manager::get_users() const {
+        return this->users;
+    }
+
+    vector<Task> Manager::get_task() const {
+        return this->tasks;
+    }
+
+    vector<Assignment> Manager::get_user_task_index() const {
+        return this->user_task_index;
+    }
+}
diff --git a/Manager.h b/Manager.h
new file mode 100644
index 0000000..98e9eb9
--- /dev/null
+++ b/Manager.h
@@ -0,0 +1,36 @@
+#include "std_lib_inc.h"
+#include "User.h"
+#include "Task.h"
+#include "Assignment.h"
+#include "DataType.h"
+#ifndef ENVIRONMENT_H
+#define ENVIRONMENT_H
+
+using models::User;
+using models::Task;
+using models::Assignment;
+
+namespace util {
+    class Manager {
+        private:
+            vector<User> users;
+            vector<Task> tasks;
+            vector<Assignment> user_task_index;
+            string filename;
+
+        public:
+            Manager();
+
+            void save();
+
+            vector<User> get_users() const;
+            vector<Task> get_task() const;
+            vector<Assignment> get_user_task_index() const;
+    };
+
+
+    inline DataType operator++(DataType& status);
+}
+
+#endif // ENVIRONMENT_H
+
diff --git a/Model.cpp b/Model.cpp
deleted file mode 100644
index 4c82500..0000000
--- a/Model.cpp
+++ /dev/null
@@ -1,15 +0,0 @@
-#include "Model.h"
-
-namespace models {
-    Model::Model() {}
-
-    Model* Model::operator>>(stringstream& stream) {
-        cout << "Default << operator was not overwritten!\n";
-        return new Model();
-    }
-
-    string Model::operator<<(Model* model) {
-        cout << "Default >> operator was not overwritten!\n";
-        return "";
-    }
-}
diff --git a/Model.h b/Model.h
deleted file mode 100644
index af38b3f..0000000
--- a/Model.h
+++ /dev/null
@@ -1,16 +0,0 @@
-#include "std_lib_inc.h"
-#ifndef MODEL_H
-#define MODEL_H
-
-namespace models {
-    class Model {
-        public: 
-            Model();
-
-            virtual Model* operator>>(stringstream& stream);
-            virtual string operator<<(Model* model);
-    };
-}
-
-#endif // MODEL_H
-
diff --git a/Task.cpp b/Task.cpp
index 2a6c509..4c03f8e 100644
--- a/Task.cpp
+++ b/Task.cpp
@@ -1,5 +1,34 @@
 #include "Task.h"
+#include "Util.h"
+#include "FormatError.h"
+
+using err::FormatError;
+using util::Util;
 
 namespace models {
-    Task::Task(const int& id, const string& name, const string& description, const vector<int>& children): Model(), id(id), name(name), description(description), children(children){}
+    Task::Task(const int& id, const string& name, const string& description, const vector<int>& children): id(id), name(name), description(description), children(children) {}
+
+    Task::Task(): id(0), name(""), description(""), children({}) {}
+
+    ostream& Task::write(ostream& stream) {
+        stream << this;
+        return stream;
+    }
+
+    int Task::get_id() const {
+        return this->id;
+    }
+
+    string Task::get_name() const {
+        return this->name;
+    }
+
+    string Task::get_description() const {
+        return this->description;
+    }
+
+    vector<int> Task::get_children() const {
+        return this->children;
+    }
+
 }
diff --git a/Task.h b/Task.h
index a976256..8d5cfad 100644
--- a/Task.h
+++ b/Task.h
@@ -1,10 +1,14 @@
 #include "std_lib_inc.h"
-#include "Model.h"
+#include "FormatError.h"
+#include "Util.h"
 #ifndef TASK_H
 #define TASK_H
 
+using err::FormatError;
+using util::Util;
+
 namespace models {
-    class Task : public Model {
+    class Task {
         private:
             int id;
             string name;
@@ -12,9 +16,39 @@ namespace models {
             vector<int> children;
         public:
             Task(const int& id, const string& name, const string& description, const vector<int>& children);
-            Model* operator>>(stringstream& stream) override;
-            string operator<<(Model& model) override;
+
+            Task();
+
+            ostream& write(ostream& stream);
+            istream& read(istream&);
+
+            int get_id() const;
+            string get_name() const;
+            string get_description() const;
+            vector<int> get_children() const;
+
+
+            friend ostream& operator<<(ostream& os, const Task& t);
+            friend istream& operator>>(istream& is, Task& t);
     };
+
+    inline ostream& operator<<(ostream& os, const Task& t) {
+        os << t.get_id() << " " << t.get_name() << " " << t.get_description();
+        return os;
+    }
+    inline istream& operator>>(istream& is, Task& t) {
+        int id;
+        is >> id;
+        if (!is)
+            throw FormatError("Id NaN.");
+
+        string name = Util::read_string_between_percent(is);
+        string description = Util::read_string_between_percent(is);
+        vector<int> children = Util::read_numbers(is);
+
+        t = {id, name, description, children};
+        return is;
+    }
 }
 
 #endif // TASK_H
diff --git a/User.cpp b/User.cpp
index bbe66b9..649180b 100644
--- a/User.cpp
+++ b/User.cpp
@@ -1,11 +1,44 @@
 #include "User.h"
-#include <sstream>
 
 namespace models {
-    User::User(const int& id, const string& name, const string& surname): Model(), id(id), name(name), surname(surname) {}
-    Model* User::operator>>(stringstream& stream) {
-        cout << "Custom impl.";
-        return new User(0, "", "");
+    User::User(const int& id, const string& name, const string& surname): id(id), name(name), surname(surname) {}
+
+    User::User(): id(0), name(""), surname("") {}
+
+    ostream& User::write(ostream& stream) {
+        stream << this;
+        return stream;
     }
 
+    int User::get_id() const {
+        return this->id;
+    }
+
+    string User::get_name() const {
+        return this->name;
+    }
+
+    string User::get_surname() const {
+        return this->surname;
+    }
+    
+    ostream& operator<<(ostream& os, const User& u)
+    {
+        os << u.get_id() << " " << u.get_name() << " " << u.get_surname();
+        return os;
+    }
+
+    istream& operator>>(istream& is, User& u)
+    {
+        int id;
+        is >> id;
+        if (!is)
+            throw FormatError("User id NaN.");
+        string name, surname;
+        is >> name >> surname;
+        if (!is)
+            throw FormatError("Could not read user name and surname");
+        u = {id, name, surname};
+        return is;
+    }
 }
diff --git a/User.h b/User.h
index 3e2afec..c69203a 100644
--- a/User.h
+++ b/User.h
@@ -1,10 +1,14 @@
 #include "std_lib_inc.h"
-#include "Model.h"
+#include "FormatError.h"
+#include "Util.h"
 #ifndef USER_H
 #define USER_H
 
+using err::FormatError;
+using util::Util;
+
 namespace models {
-    class User : public Model {
+    class User {
         private:
             int id;
             string name;
@@ -12,9 +16,19 @@ namespace models {
 
         public:
             User(const int& id, const string& name, const string& surname);
-            Model* operator>>(stringstream& stream) override;
-            string operator<<(Model* model) override;
+            User();
+            ostream& write(ostream& stream);
+
+            int get_id() const;
+            string get_name() const;
+            string get_surname() const;
+
+            friend ostream& operator<<(ostream& os, const User& u);
+            friend istream& operator>>(istream& is, User& u);
     };
+
+    ostream& operator<<(ostream& os, const User& u);
+    istream& operator>>(istream& is, User& u);
 }
 
 #endif // USER_H
diff --git a/UserTaskIndex.cpp b/UserTaskIndex.cpp
deleted file mode 100644
index ed7e0f5..0000000
--- a/UserTaskIndex.cpp
+++ /dev/null
@@ -1,5 +0,0 @@
-#include "UserTaskIndex.h"
-
-namespace models {
-    UserTaskIndex::UserTaskIndex(const int& user_id, const int& task_id) : Model(), user_id(user_id), task_id(task_id) {}
-}
diff --git a/UserTaskIndex.h b/UserTaskIndex.h
deleted file mode 100644
index 2bffb2d..0000000
--- a/UserTaskIndex.h
+++ /dev/null
@@ -1,19 +0,0 @@
-#include "std_lib_inc.h"
-#include "Model.h"
-#ifndef USERTASKINDEX_H
-#define USERTASKINDEX_H
-
-namespace models {
-    class UserTaskIndex : public Model{
-        private:
-            int user_id;
-            int task_id;
-        public:
-            UserTaskIndex(const int& user_id, const int& task_id);
-            Model* operator>>(stringstream& stream) override;
-            string operator<<(Model& model) override;
-    };
-}
-
-#endif // USERTASKINDEX_H
-
diff --git a/Util.cpp b/Util.cpp
new file mode 100644
index 0000000..b7c97e6
--- /dev/null
+++ b/Util.cpp
@@ -0,0 +1,68 @@
+#include "Util.h"
+#include "FormatError.h"
+#include <cstdio>
+#include <exception>
+#include <string>
+
+using err::FormatError;
+
+namespace util {
+    string Util::read_string_between_percent(istream& is) {
+        char c;
+        string s = "";
+        bool read = false;
+
+        for(int i = 0; i < 2; ++i) {
+            while (true) {
+                is >> c;
+                if (!is)
+                    throw FormatError("Could not read char!");
+                if (c == '%') {
+                    read = !read;
+                    break;
+                }
+                if (!read)
+                    continue;
+                s += c;
+            }
+        }
+
+        return s;
+    }
+
+    vector<int> Util::read_numbers(istream &is) {
+        int i;
+        string until_eol;
+        getline(is, until_eol);
+
+        vector<string> numbers_as_string = Util::split(until_eol);
+        vector<int> nums;
+
+        try {
+            for(string s : numbers_as_string)
+                nums.push_back(stoi(s));
+        } catch (exception& _) {
+            throw FormatError("Could not convert string to int");
+        }
+
+        return nums;
+    }
+
+    vector<string> Util::split(const string& s) {
+        vector<string> strs;
+        string result = "";
+
+        for(char c : s) {
+            if (c == ' ') {
+                if (result != "") {
+                    strs.push_back(result);
+                    result = "";
+                }
+                break;
+            }
+            result += c;
+        }
+
+        return strs;
+    }
+}
diff --git a/Util.h b/Util.h
new file mode 100644
index 0000000..7806cc4
--- /dev/null
+++ b/Util.h
@@ -0,0 +1,14 @@
+#include "std_lib_inc.h"
+#ifndef UTIL_H
+#define UTIL_H
+
+namespace util {
+    class Util {
+        public:
+            static string read_string_between_percent(istream& is);
+            static vector<int> read_numbers(istream& is);
+            static vector<string> split(const string& s);
+    };
+}
+
+#endif // UTIL_H
diff --git a/main.cpp b/main.cpp
index a2e63d6..feee681 100644
--- a/main.cpp
+++ b/main.cpp
@@ -3,33 +3,51 @@
 #include "SubCommand.h"
 #include "HelpCommand.h"
 #include "AddCommand.h"
+#include "User.h"
+#include "Manager.h"
+#include <exception>
+
+#include "FileError.h"
 
 using commands::SubCommand;
 using commands::HelpCommand;
 using commands::AddCommand;
+using util::Manager;
+using err::FileError;
+using err::FormatError;
 
 const vector<SubCommand*> handlers = { new HelpCommand(), new AddCommand() };
 
-// Mein Leben auf IMDB, nur 7/10.
-
 int main(int argc, char** argv)
 {
     if (argc < 2) {
         cout << "There are not enough args!\n";
         return 0;
     }
+
     stringstream parameter = make_string_stream(argc, argv);
     string command;
     parameter >> command;
 
-    for (SubCommand* sc : handlers) {
-        if (sc->get_name() == command) {
-            sc->run(argc, parameter);
-            return 0;
+    try {
+        for (SubCommand* sc : handlers) {
+            if (sc->get_name() == command) {
+                sc->run(argc, parameter);
+                return sc->get_value();
+            }
         }
     }
-
-    cout << "I don't know this command!\n";
-    return 0;
+    catch (FormatError& e) {
+        cout << e.why() << "\n";
+    }
+    catch (FileError& e)
+    {
+        cout << e.why() << "\n";
+    }
+    catch (exception& e) {
+        cout << e.what() << "\n";
+    } 
+    return 101;
 }
 
+