Added Ruby Version file
My first Cucumber feature
Execute everything with nice rake tasks
Acceptance tests for joining and leaving lobbies
Acceptance test for listing lobbies
API Change: Lobby#game also returns `is_finished`
Acceptance tests: Also check if the game was started
Adding Rack for Testing
Acceptance test for GET and POST game
API Refinement: Updating a vertex is optional
Feature Spec: Updating the position of a player