DAO almost finished.

Implemented function to get and insert data in the database. Know it is possible:

-To save a game
-To retrieve a game given its ID
-To save a move given a game and a move
-To retrieve one move given the game and the number of the move in that game (starting from 1)
-To retrieve the whole list of moves of a game (returned as ArrayList)
-To save the players of a game
-To retrieve the players of a game given that game
-Tp save users
-To retrieve users given either their id, they email or nickname