Create empty class file.
Add basic Piece methods.

Methods: initialize, basic accessors, self.slide_moves, self.jump_moves, to_s, location, king?
Add basic Tile methods.

Methods: Initialize, accessors, to_s, empty?, occupied?.
Add basic methods to board class.

Methods: Initialize (generate_board / generate_tiles), accessors, tile, display.
Added very basic methods to Checkers class.

Methods: Initialize, play, accessors, requires.
Added basic Player methods.

Methods: Initialize, origin, accessors.
Change piece color attribute to player. Add starting_locations method.
Change tile location to coordinate, added add_piece method.
In Piece: Change location to coordinate, fix broken to_s method...

Edited mistake on accessor.
In Player: Added starting_locations method, fixed origin to depend...

... on Board::SIZE, included MoveOps module.
In Checkers: edit initialize to add players, add players method.
In Board: Add constants, add add_pieces method, chang location to ...

... coordinate, edit initialize board generation method.
Add module MoveOps with common move operation.
In Tile: bugfix in remove_piece method.
In Piece: Added move methods (jump, slide, move) and helpers...

...fix to_s, use hash in self.slide_moves & self.jump_moves.
In Board: Fix display & DISPLAY_MOVES.
In Piece: raise error for illegal moves.
In Piece: methods for finding legal jump and slide moves.
In Checkers: Added play loop. Players take game when initializing.
In Player: take game when initialing, add HumanPlayer clas with input methods for play loop.