Rename exercises dir

Name it instead "topics" so it won't be
strange if some topics included "exercises" directory.

topics/flask_container_ci2/app/config.py

@@ -0,0 +1,11 @@
+#!/usr/bin/env python
+# coding=utf-8
+
+import os
+
+basedir = os.path.abspath(os.path.dirname(__file__))
+
+SECRET_KEY = 'shhh'
+CSRF_ENABLED = True
+
+SQLALCHEMY_DATABASE_URI = 'sqlite:///' + os.path.join(basedir, 'app.db')