Updated Heroku docs, fixed heroku build (fossasia#333)

* added runtime.txt

* exact python version

* added a base level requirements

* added migrate command to Procfile

* fixed Procfile, run open_event

* added updated heroku deploy instructions

* updated HowtoDeploytoHeroku.md

* updated docs

Author: aviaryan

Procfile

@@ -1 +1,2 @@
-web: gunicorn run:current_app
+web: gunicorn open_event:app
+migrate: python manage.py db upgrade

docs/HowtoDeploytoHeroku.md

@@ -1,31 +1,22 @@
 # How to deploy server to Heroku
 
-Here are the steps:
+### Steps
 
-* We need to install heroku on our machine.Type the following in your linux terminal:
+* We need to install heroku on our machine. Type the following in your linux terminal:
 	* ```wget -O- https://toolbelt.heroku.com/install-ubuntu.sh | sh```
   This installs the Heroku Toolbelt on your machine to access heroku from the command line.
-* Next we need to login to our heroku server(assuming that you have already created an account).Type the following in the terminal:
+* Next we need to login to our heroku server (assuming that you have already created an account). Type the following in the terminal:
 	* ```heroku login```
-  You will see the following output:
-	Enter your Heroku credentials.
-	Email: [email protected]
-	Password (typing will be hidden):
-	Logged in as [email protected]
-* Once logged in we need to create a space on the heroku server for our application.This is done with the following command
+    * Enter your credentials and login.
+* Once logged in we need to create a space on the heroku server for our application. This is done with the following command
 	* ```heroku create```
-* We need to initialize our git repository and push the master branch of our repository to heroku.Type:
-	* ```git init```
-  If the commit isn't changed to master we need to do so by typing the following commands on terminal:
-	* ```git add -A```
-	* ```git commit -m "Initial Commit."```
-	* ```git push origin master```
-* Next we create our requirements.txt file using the pip command:
-	* ```pip freeze > requirements.txt```
-* The next step is creating a Procfile. This can be done by using a production ready web server called gunicorn.The contents of   the Procfile will be:
-	* ```web: gunicorn <app>:app```
-  Here, the <app> will be replaced by the name of the application without the .py at its end.Basically a Procfile tells heroku   what to name our process which runs our   web application.
-* Before deploying to heroku, make sure that the app works locally on the designated port.
-* Finally we deploy the code to heroku.Its very simple, just type:
-	* ```git push heroku master```
-  At the end of the process a URL will be generated where our flask application will run.
+* Once the app is created, now it's time to set the `DATABASE_URL` env var.
+    * ```heroku config:set DATABASE_URL=postgresql://postgres:start@localhost/test```
+* After setting env vars, create the heroku database.
+    * ```heroku addons:create heroku-postgresql:hobby-dev```
+    * ```heroku pg:promote <HEROKU_POSTGRESQL_COLOR_URL>```
+* Then we deploy the code to heroku.
+	* ```git push heroku master``` or
+    * ```git push heroku yourbranch:master``` if you are in a different branch than master
+* Finally, time to create tables on the server. Also in case of model updates, run the following command -
+    * ```heroku run migrate```

open_event/__init__.py

@@ -79,3 +79,7 @@ def request_wants_json():
         request.accept_mimetypes['text/html']
 
 current_app, manager, database = create_app()
+
+
+if __name__ == '__main__':
+    current_app.run()

requirements.txt

@@ -0,0 +1 @@
+-r requirements/prod.txt

runtime.txt

@@ -0,0 +1 @@
+python-2.7.11