TG-33 fix cas auth

backend/app/api/loginAPI.py

@@ -3,7 +3,7 @@ from flask_restful import Resource
 from flask_restful.reqparse import RequestParser
 
 from app.model import *
-
+from app.core import cas
 
 class LoginAPI(Resource):
     """

backend/requirements/common.txt

@@ -2,6 +2,7 @@ flask < 0.13
 flask-script < 2.1
 flask-sqlalchemy < 2.2
 flask-restful < 0.4
+flask-cas
 mysqlclient < 1.4
 pdfjinja < 1.1
 PyPDF2 < 1.27