ArrayList einer Objektklasse wird nicht initialisiert

Ich lasse eine Klasse von HomeworkDatabase mit einer von mir erstellten ArrayList arbeiten. Es gibt wahrscheinlich viele Fehler in meinem Code, da ich noch ein Anfänger bin. Ich verstehe nur nicht, warum es in der Hauptsache nicht initialisiert wird. Hier ist mein Code:

HomeworkDatabase.h:

#ifdef HomeworkDatabase_H
#define HomeworkDatabase_H

class HomeworkDatabase
{
        private:

                string className;
                string homework;
                int dueDate;

       public:

             HomeworkDatabase(string className, string homework, int dueDate);
                HomeworkDatabase();
                string getClass();
                string getHomework();
                int getDueDate();
};

#endif

HomeworkDatabase.cpp:

#include "HomeworkDatabase.h"
#include <iostream>
#include <string>
using namespace std;

HomeworkDatabase::HomeworkDatabase( string className, string homework, int    dueDate)
{
        this->className = className;
        this->homework = homework;
        this->dueDate = dueDate;
}

HomeworkDatabase::HomeworkDatabase()
{
        this->dueDate = NULL;
}

string getClass::getClass()
{
        return className;
}

string getHomework::getHomework()
{
        return homework;
}

int getDueDate::getDueDate()
{
        return dueDate;

HomeworkArrayList.cpp:

#include <iostream>
#include <string>
#include "HomeworkDatabase.h"

using namespace std;

template <class HomeworkDatabase>
class HomeworkArrayList
{
    private:

            int maxSize;
            int curr;
            int listSize;
            HomeworkDatabase* homework;

    public:

            HomeworkArrayList(int size)
            {
                    maxSize = size;
                    listSize = 0;
                    curr = 0;
                    homework = new HomeworkDatabase[size];
            }

            ~HomeworkArrayList()
            {
                    delete [] homework;
            }

            void append(const HomeworkDatabase& object )
            {
                    homework[listSize] = object;
                    listSize++;
            }

            void frontOfList()
            {
                    curr = 0;
            }

            void backOfList()
            {
                    curr = listSize;
            }

            void prev()
            {
                    curr--;
            }

            void next()
            {
                    curr++;
            }

            int getSize()
            {
                    return listSize;
            }
 }

HomeworkMain.cpp:

#include <iostream>
#include <string>
#include "HomeworkArrayList.cpp"
#include "HomeworkDatabase.h"

using namespace std;

int main()
{
        HomeworkArrayList<HomeworkDatabase> today = HomeworkArrayList<HomeworkDatabase>(50);
        HomeworkDatabase one("Intro to Programming","Read Chapter 1", 12);
        return 0;
}

Hauptsächlich bekomme ich die Fehler:

HomeworkMain.cpp:11:9: error: ‘HomeworkDatabase’ was not declared in this scope
HomeworkMain.cpp:10:43: error: template argument 1 is invalid