3. Game owner specifies game name that already exists

Given that game owner has game name n entered
and game owner has another unfinished game with name n
When game owner initiates game creation
Then an error message that the game with the name n already exists is displayed

Also added Players controller since now game owner is hardcoded and it  kinda sucks, but oh well, players management wasn't a part of this user story, I could say we had major planning bug :)