update index.md (#29446)

Added short flask guide

guide/english/python/setting-up-python-web-framework-django-and-flask/index.md

@@ -19,7 +19,7 @@ So, let's create a virtual environment (also called a virtualenv). Virtualenv wi
 
 For more information on virtual environments see the relevent section <a href='https://guide.freecodecamp.org/python/virtual-environments/' target='_blank' rel='nofollow'>here</a>.
 
-## Wrapping Up
+## Django
 
 If you have already installed `pip` then simply:
 ```
@@ -40,3 +40,30 @@ In next article, we would be discussing how to install PostgreSQL and use it wit
 A point to ponder - we have been using `pip` heavily, but we have barely said anything about it. Well, for now, it's just a package manager like `npm`. It has some differences with `npm`; but, you don't need to worry about that now. If you are interested, do check out the <a href='http://pip-python3.readthedocs.org/en/latest/index.html' target='_blank' rel='nofollow'>official `pip` documentation</a>.
 
 <em>If you have suggestions or questions, come join us on <a href='https://gitter.im/FreeCodeCamp/home' target='_blank' rel='nofollow'>gitter</a></em>.
+
+## Flask
+
+### Install Flask
+```
+$ pip install Flask
+```
+After installation create a test file ```freecodecamp.py```:
+
+```
+from flask import Flask
+app = Flask(__name__)
+
+@app.route("/")
+def hello():
+    return("Hello FreeCodeCamp!")
+
+```
+Run the flask application.
+```
+$ FLASK_APP=freecodecamp.py flask run
+```
+To see the ```freecodecamp.py``` file in web browser:
+
+Go to `http://localhost:5000`and you should see "Hello FreeCodeCamp!".
+
+More about flask documentation at <a href='http://flask.pocoo.org/docs/1.0/'>Flask docs</a>