Include save functionality
Disallow pawn forward captures
Add check logic
Exclude moves that leave king in check
Include .gitignore
Add checkmate logic
File cleanup and use green dots for possible moves
Change all occurrences of 'position' to 'coordinates'
Cleanup of board.rb
Fix bad coordinates bug
Squash bugs
Cleanup of piece character assignment
Clean up pieces.rb
Clean up renderer.rb
Clean up chess.rb
Clean up board.rb