Add Move, BoardState models
Update gitignore
Add skeleton for helper classes validating the moves and updating the board
Move validation

I implemented the move validation as well as
making the move. I also wrote code for the parse_move
method but actually I am not sure if we really need it.
Concerning the figures I used 2-letter strings to represent them. I
think validation is easier like this.
Display empty chess board

Added some code to display an empty chess board.
This can certainly be done more elegant. But I think
to start with it is not bad.
Mouse click on chess board

I added a function to handle mouse clicks on the chess board. This
function also converts the mouse position into file and rank of the
corresponding position.
Games index; current_games index
Merge branch 'game' of https://github.com/PerezReyLorena/WE_Mini-Project into game
Add link to chess rules; add board_state entry on game creation
Add uploading images. Run 'bundle install' and restart server
Remove images from uploads
Implement main functions of the games and moves controllers; generate DrawRequests model
Implements draw requests