Backport comments from docs.

Author: alexchamberlain

README.md

@@ -13,19 +13,19 @@ orginally developed for Bloomberg's GHE install.
 receives push events all it takes is:
 
 ```py
-from flask import Flask
 from github_webhook import Webhook
+from flask import Flask
 
-app = Flask(__name__)
-webhook = Webhook(app)
+app = Flask(__name__)  # Standard Flask app
+webhook = Webhook(app) # Defines '/postreceive' endpoint
 
-@app.route("/")
+@app.route("/")        # Standard Flask endpoint
 def hello_world():
     return "Hello, World!"
 
-@webhook.hook()
+@webhook.hook()        # Defines a handler for the 'push' event
 def on_push(data):
-    print "Got push with: {0}".format(data)
+    print("Got push with: {0}".format(data))
 
 if __name__ == "__main__":
     app.run(host="0.0.0.0", port=80)