angular select 默认选中指定项 option动态渲染

<select ng-model="com.game_id" ng-options="x.game_id as x.game_name for x in game_info"></select>

$scope.game_info = [{game_id : 0 , game_name:'全部游戏'},{game_id : 1 , game_name:'穿越火线'},{game_id : 2 , game_name:'地下城与勇士'},{game_id : 3 , game_name:'使命召唤'},{game_id : 4 , game_name:'英雄联盟'},{game_id : 5 , game_name:'逆战'},];$ = {game_id:0//指定项，｝

如图所示：