Simplify Config setup and move some functions to dedicated files

tests/test_user_model.py

@@ -1,12 +1,13 @@
-import unittest
-import time
 from app import create_app, db
 from app.models import User, AnonymousUser, Role, Permission
+from . import TestConfig
+import time
+import unittest
 
 
 class UserModelTestCase(unittest.TestCase):
     def setUp(self):
-        self.app = create_app('testing')
+        self.app = create_app(TestConfig)
         self.app_context = self.app.app_context()
         self.app_context.push()
         db.create_all()