新增从group中移除元素

core/model/User.coffee

@@ -32,7 +32,7 @@ module.exports = class User extends Model
   # @group 可以是数组，也可以是字符串，但是必须在['admin','user','trial']中
   # @callback 第一个参数是err,第二个参数是添加分组后的model
   # 用法：
-  #     user.addToGroup ['admin','users'],(err,result)->
+  #     user.addToGroup ['admin','user'],(err,result)->
   #       console.log result
   # 或
   #     user.addToGroup 'admin',(err,result)->
@@ -40,8 +40,20 @@ module.exports = class User extends Model
   addToGroup: (group,callback) ->
     group = [].push group if not _.isArray group
     for i in group
-      throw 'bad group' if i not in @constructor.validateData['group']
+      throw 'unknown group' if i not in @constructor.validateData['group']
     @update $addToSet:
       group:
         $each:group
+    ,callback
+  #从分组中移除
+  # @group [string]，必须在['admin','user','trial']中
+  # @callback 第一个参数是err,第二个参数是移除分组后的model
+  # 用法：
+  #     user.removeFromGroup 'user',(err,result)->
+  #       console.log result
+  removeFromGroup: (group,callback) ->
+    throw 'group must be string' if not _.isString group
+    throw 'unknown group' if group not in @constructor.validateData['group']
+    @update $pull:
+      group: group
     ,callback