Add Atlas getting started link to README

Author: alexbevi

README.md

@@ -1,5 +1,9 @@
 # Django MongoDB Backend
 
+Django MongoDB Backend is a [Django]((https://docs.djangoproject.com/)
+database backend that uses [PyMongo](https://www.mongodb.com/docs/languages/python/pymongo-driver/)
+to connect to MongoDB.
+
 ## Documentation
 
 Documentation written in the style of MongoDB's documentation is available at
@@ -38,6 +42,10 @@ django-admin --version
 
 ### Connect to the database
 
+If you don't already have a MongoDB cluster, see the
+[getting started with Atlas](https://www.mongodb.com/docs/atlas/getting-started/)
+documentation to quickly and easily [deploy a free cluster](https://www.mongodb.com/docs/atlas/tutorial/deploy-free-tier-cluster/).
+
 Navigate to your `example/settings.py` file and replace the `DATABASES`
 setting like so: