change relation name in player/team model : game -> current_game
game_stat method added to player/team model
[#72304500] keep track of a team's games
fix broken tests
web gui bugfix
remove has_many :teams relations from game model
[#72355928] do not allow to add/remove a player to/from a team if the team is playing
remove has_many :players relations from game model
replace POST /games/:id/add_team/:team_id with POST /games/:id/add_home_team and POST /games/:id/add_away_team
[#71700066] create a new game
when creating a new game, home and away team should be different
[#72386892] remove a game
[#72387280] delete a team
refactor test
add .name method to get a match name of a game
[#72388098] remove a game - webgui
[#72388108] after removing a game, null game score displayed
merge feature/previous_game_tracking to master