anchor.diff:  
   Once a match has been started, any player currently belonging to the game is allowed to make moves. It is up to the game itself to determine which players may play and when.
   
  -However, one is only allowed to post a move if he is synchronized with the current state of the game. This is done with a parameter named `last_move_id`. Every move made by one of the players, this value changes and is returned in the message posted to the other players. The next player must post this value along with his next move, else he will receive an error indicating that he needs to be resynchronized.
  +However, one is only allowed to post a move if he is synchronized with the current state of the game. This is done with a parameter named `last_event_id`. Every move made by one of the players, this value changes and is returned in the message posted to the other players. The next player must post this value along with his next move, else he will receive an error indicating that he needs to be resynchronized.
   
   A move is made of a `move` object (which is basically freeform, and represents a message that will be sent to other players indicating what changed) and an optional game state labelled `global_state`. A global game state sould be enough for any player who joins the game to restore the game locally. Thus, when a global state is posted, the list of moves is cleared on the server: only the moves made since the last global state are kept and posted to people who join the game. As such, one can reconstruct the current game by starting from the global state and applying the pending moves.
   
  -When a move is posted, all players get notified in the form of an event, taking the following form:
  +When a move is posted, all players get notified in the form of an event, looking as follows:
   
       {
  -        "type": "match.move",
  -        "event": {
  -            "_id": "54784176a8df72000049340e",
  -            "player_id": "547841755e4cfe0000bf6907",
  -            "move": {
  -                "what": "changed"
  -            },
  -            "global_state": {
  -                "full": "game_state"
  -            }
  -        },
  -        "id": "d0fb71c1-3cd0-4bbd-a9ec-29cb46cf9203"
  +        "type": "match.move",
  +        "event": {
  +            "_id": "54784176a8df72000049340e",
  +            "player_id": "547841755e4cfe0000bf6907",
  +            "move": {
  +                "what": "changed"
  +            },
  +            "global_state": {
  +                "full": "game_state"
  +            }
  +        },
  +        "id": "d0fb71c1-3cd0-4bbd-a9ec-29cb46cf9203"
       }
   
   + Request (application/json)
  
positive.code: 
  Join an existing match.
  
  + Request (application/json)
  
      + Parameters
  
negative.code: + Response 200 (application/json)
  
          {
              "match": {
                  "game_id": "545a05d2fd2e2eab09077615",
                  "match_id": "547841765e4cfe0000bf6909",
                  "creator": "547841755e4cfe0000bf6907",
                  "status": "running",
                  "description": "Sample match for testing",
                  "custom_properties": {
                      "type": "coop"
                  },
                  "max_players": 3,
                  "players": [
                      "547841755e4cfe0000bf6907",
                      "547841765e4cfe0000bf6908"
                  ],
                  "last_event_id": "54784176a8df72000049340e",
                  "events": [
                      {
                          "type": "match.move",
                          "event": {
                              "_id": "54784176a8df72000049340e",
                              "player_id": "547841755e4cfe0000bf6907",
                              "move": {
                                  "what": "changed"
                              },
                              "global_state": {
                                  "full": "game_state"
                              }
                          }
                      }
                  ],
                  "global_state": {
                      "full": 1
                  }
              }
          }
  
  + Response 400 (application/json)
  