Add Flask

Fixes: #710
Co-Authored-By: Parth Waidya <parthwaidya@gmail.com>

f/flask.py

@@ -0,0 +1,9 @@
+from flask import Flask
+app = Flask(__name__)
+
+@app.route("/")
+def hello():
+    return "Hello World"
+
+if __name__ == "__main__":
+    app.run()