Merge pull request #1538 from springcoil/docker

DOCS: Clarified the developing in docker part of CONTRIBUTING.md

Author: AustinRochford

CONTRIBUTING.md

@@ -110,9 +110,9 @@ tools:
 We have provided a Dockerfile which helps for isolating build problems, and local development.
 Install [Docker](https://www.docker.com/) for your operating system, clone this repo, then
 run `./scripts/start_container.sh`. This should start a local docker container called `pymc3`,
-as well as a [`jupyter`](http://jupyter.org/) notebook server running on port 8888.  The repo
-will be running the code from your local copy of `pymc3`, so it is good for development.  You may
-also use it to run the test suite, with
+as well as a [`jupyter`](http://jupyter.org/) notebook server running on port 8888. You will have to open
+a browser at `localhost:8888`. The repo will be running the code from your local copy of `pymc3`, 
+so it is good for development.  You may also use it to run the test suite, with
 
 ```bash
 $  docker exec -it pymc3  bash # logon to the container