Add flask

Dockerfile

@@ -413,6 +413,8 @@ RUN pip install flashtext && \
     pip install pytorch-lightning && \
     pip install datatable && \
     pip install sympy && \
+    # flask is used by agents in the simulation competitions.
+    pip install flask && \
     # pycrypto is used by competitions team.
     pip install pycrypto && \
     /tmp/clean-layer.sh

tests/test_flask.py

@@ -0,0 +1,10 @@
+import unittest
+
+from flask import Flask, request
+
+class TestFlask(unittest.TestCase):
+    def test_request(self):
+        app = Flask(__name__)
+        with app.test_request_context('/foo', method='POST'):
+            assert request.path == '/foo'
+            assert request.method == 'POST'