Rename exercises dir

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

topics/flask_container_ci2/tests.py

@@ -0,0 +1,25 @@
+#!/usr/bin/env python
+# coding=utf-8
+
+import unittest
+
+from app import main
+
+
+class TestCase(unittest.TestCase):
+
+    def setUp(self):
+        self.app = main.app.test_client()
+
+    def test_main_page(self):
+        response = self.app.get('/', follow_redirects=True)
+        self.assertEqual(response.status_code, 200)
+
+    def test_matrix(self):
+        response = self.app.get('/matrix/123n459,789', follow_redirects=True)
+        # Change when the matrix route is fixed and returning the actual matrix
+        self.assertEqual(response.status_code, 500)
+
+
+if __name__ == '__main__':
+    unittest.main()