Run testproj in a Heroku demo app (#38)

* Add Heroku configuration
* Add links in API description
* Read database connection string from DATABASE_URL environment variable
* Restructure settings files for production
* Run server using gunicorn and servce static files with whitenoise
* Install drf-yasg from source instead of pypi in testproj
* Add readme links to demo app

requirements/dev.txt

@@ -2,3 +2,6 @@
 -r tox.txt
 -r test.txt
 -r lint.txt
+
+tox-battery>=0.5
+detox>=0.11

requirements/heroku.txt

@@ -0,0 +1,9 @@
+# requirements necessary when deploying the test project to heroku
+.[validation]
+Django>=1.11.7,<2.0; python_version <= "2.7"
+Django>=1.11.7; python_version >= "3.4"
+
+-r testproj.txt
+psycopg2>=2.7.3
+gunicorn>=19.7.1
+whitenoise>=3.3.1

requirements/testproj.txt

@@ -5,3 +5,5 @@ django-cors-headers>=2.1.0
 django-filter>=1.1.0,<2.0; python_version == "2.7"
 django-filter>=1.1.0; python_version >= "3.4"
 djangorestframework-camel-case>=0.2.0
+dj-database-url>=0.4.2
+user_agents>=1.1.0

requirements/tox.txt

@@ -1,6 +1,4 @@
 # requirements for building and running tox
 tox>=2.9.1
-tox-battery>=0.5
-detox>=0.11
 
 -r setup.txt