Add heroku configuration file

{{cookiecutter.repo_name}}/README.rst

@@ -205,6 +205,9 @@ We providing tools and instructions for deploying using Docker and Heroku.
 Heroku
 ^^^^^^
 
+.. image:: https://www.herokucdn.com/deploy/button.png
+    :target: https://heroku.com/deploy
+
 Run these commands to deploy the project to Heroku:
 
 .. code-block:: bash

{{cookiecutter.repo_name}}/app.json

@@ -0,0 +1,30 @@
+{
+  "name": "{{cookiecutter.repo_name}}",
+  "description": "{{cookiecutter.description}}",
+  "env": {
+    "BUILDPACK_URL": "https://github.com/heroku/heroku-buildpack-python",
+    "DJANGO_SETTINGS_MODULE": "config.settings.production",
+    "DJANGO_SECRET_KEY": {
+      "description": "A secret key for verifying the integrity of signed cookies.",
+      "generator": "secret"
+    },
+    "DJANGO_ALLOWED_HOSTS": {
+      "description": "Comma-separated list of hosts",
+      "value": ".herokuapp.com"
+    },
+    "DJANGO_AWS_ACCESS_KEY_ID": "",
+    "DJANGO_AWS_SECRET_ACCESS_KEY": "",
+    "DJANGO_AWS_STORAGE_BUCKET_NAME": "",
+    "DJANGO_MAILGUN_SERVER_NAME": "",
+    "DJANGO_MAILGUN_API_KEY": ""{% if cookiecutter.use_sentry == "y" -%},
+    "DJANGO_SENTRY_DSN": ""{%- endif %}
+  },
+  "scripts": {
+    "postdeploy": "python manage.py migrate"
+  },
+  "addons": [
+    "heroku-postgresql:hobby-dev",
+    "heroku-redis:hobby-dev",
+    "mailgun"
+  ]
+}