修正dispatcher，使用redis存任务队列，修正submission的post，修改部分settings

submission/tasks.py

@@ -1,7 +1,8 @@
+from __future__ import absolute_import, unicode_literals
 from celery import shared_task
-from judge.tasks import JudgeDispatcher
+from judge.dispatcher import JudgeDispatcher
 
 
 @shared_task
-def _judge(submission_obj, problem_obj):
-    return JudgeDispatcher(submission_obj, problem_obj).judge()
+def judge_task(submission_id, problem_id):
+    JudgeDispatcher(submission_id, problem_id).judge()