Added the files from the tutorial

Procfile

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+web: gunicorn app:app --log-file=-

app.py

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+import os
+import sys
+import json
+from datetime import datetime
+
+import requests
+from flask import Flask, request
+
+app = Flask(__name__)
+
+
+@app.route('/', methods=['GET'])
+def verify():
+    # when the endpoint is registered as a webhook, it must echo back
+    # the 'hub.challenge' value it receives in the query arguments
+    if request.args.get("hub.mode") == "subscribe" and request.args.get("hub.challenge"):
+        if not request.args.get("hub.verify_token") == os.environ["VERIFY_TOKEN"]:
+            return "Verification token mismatch", 403
+        return request.args["hub.challenge"], 200
+
+    return "Hello world", 200
+
+
+@app.route('/', methods=['POST'])
+def webhook():
+
+    # endpoint for processing incoming messaging events
+
+    data = request.get_json()
+    log(data)  # you may not want to log every incoming message in production, but it's good for testing
+
+    if data["object"] == "page":
+
+        for entry in data["entry"]:
+            for messaging_event in entry["messaging"]:
+
+                if messaging_event.get("message"):  # someone sent us a message
+
+                    sender_id = messaging_event["sender"]["id"]        # the facebook ID of the person sending you the message
+                    recipient_id = messaging_event["recipient"]["id"]  # the recipient's ID, which should be your page's facebook ID
+                    message_text = messaging_event["message"]["text"]  # the message's text
+
+                    send_message(sender_id, "roger that!")
+
+                if messaging_event.get("delivery"):  # delivery confirmation
+                    pass
+
+                if messaging_event.get("optin"):  # optin confirmation
+                    pass
+
+                if messaging_event.get("postback"):  # user clicked/tapped "postback" button in earlier message
+                    pass
+
+    return "ok", 200
+
+
+def send_message(recipient_id, message_text):
+
+    log("sending message to {recipient}: {text}".format(recipient=recipient_id, text=message_text))
+
+    params = {
+        "access_token": os.environ["PAGE_ACCESS_TOKEN"]
+    }
+    headers = {
+        "Content-Type": "application/json"
+    }
+    data = json.dumps({
+        "recipient": {
+            "id": recipient_id
+        },
+        "message": {
+            "text": message_text
+        }
+    })
+    r = requests.post("https://graph.facebook.com/v2.6/me/messages", params=params, headers=headers, data=data)
+    if r.status_code != 200:
+        log(r.status_code)
+        log(r.text)
+
+
+def log(msg, *args, **kwargs):  # simple wrapper for logging to stdout on heroku
+    try:
+        if type(msg) is dict:
+            msg = json.dumps(msg)
+        else:
+            msg = unicode(msg).format(*args, **kwargs)
+        print u"{}: {}".format(datetime.now(), msg)
+    except UnicodeEncodeError:
+        pass  # squash logging errors in case of non-ascii text
+    sys.stdout.flush()
+
+
+if __name__ == '__main__':
+    app.run(debug=True)

readme.md

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+# Facebook Messenger Bot
+This is a simple python template that uses Flask to build a webhook for Facebook's Messenger Bot API.
+
+Read more in my [tutorial that uses this repository](https://blog.hartleybrody.com/fb-messenger-bot/).
+
+*New:* [Check out my Facebook Messenger Bot Course](https://facebook-messenger-bot.teachable.com/p/facebook-messenger-bot/). It walks you through the process of getting this bot hosted on heroku step-by-step, and also unlocks all the content that's hidden in this repo's branches.
+
+## "Callback verification failed"
+
+![Facebook Error](https://cloud.githubusercontent.com/assets/18402893/21538944/f96fcd1e-cdc7-11e6-83ee-a866190d9080.png)
+
+The #1 error that gets reported in issues is that facebook returns an error message (like above) when trying to add the heroku endpoint to your facebook chat application.
+
+Our flask application intentionally returns a 403 Forbidden error if the token that facebook sends doesn't match the token you set using the heroku configuration variables.
+
+If you're getting this error, it likely means that you didn't set your heroku config values properly. Run `heroku config` from the command line within your application and verify that there's a key called `VERIFY_TOKEN` that has been set, and that it's set to the same value as what you've typed into the window on facebook.

requirements.txt

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+Flask==0.11.1
+Jinja2==2.8
+MarkupSafe==0.23
+Werkzeug==0.11.10
+click==6.6
+gunicorn==19.6.0
+itsdangerous==0.24
+requests==2.10.0
+wsgiref==0.1.2

runtime.txt

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+python-2.7.14