Add a plethora of errors to the leaderboard updater

lib/user.js

@@ -131,12 +131,13 @@ user.prototype.donePlaying = function() {
     clearInterval(this.get('playTimer'));
 };
 
-user.prototype.updateLeaderboard = function(board, value) {
+user.prototype.updateLeaderboard = function(board, value, callback) {
     // TODO: Throttle this function.
 
     var currentlyPlaying = this.get('currentlyPlaying');
     // Check that the user is playing a game.
     if (!currentlyPlaying) {
+        callback('not_playing_a_game');
         return;
     }
 
@@ -145,6 +146,7 @@ user.prototype.updateLeaderboard = function(board, value) {
         value === 0 ||
         value < -1 * MAX_LEADERBOARD_INCR ||
         value > MAX_LEADERBOARD_INCR) {
+        callback('invalid_increment');
         return;
     }
 
@@ -154,7 +156,10 @@ user.prototype.updateLeaderboard = function(board, value) {
         currentlyPlaying,
         board,
         function(exists) {
-            if (!exists) return;
+            if (!exists) {
+                callback('invalid_board');
+                return;
+            }
 
             leaderboard.updateLeaderboard(
                 this.dataChannel,