Merge branch 'educoder' into dev_aliyun

app/models/competition_team.rb

@@ -11,7 +11,8 @@ class CompetitionTeam < ActiveRecord::Base
   # attr_accessible :invite_code, :name, :team_type
 
   def teacher
-    User.where(:id => self.teacher_id).first
+    teacher_id = self.teachers.first&.user_id
+    User.find_by(id: teacher_id)
   end
 
   def group_members