Contributor Ramp up (#190)

* added build job to documentation

* added redis backend

* rewrite invoke build line

Author: dakonr

README.md

@@ -76,6 +76,7 @@ The project is following Network to Code software development guidelines and are
 - pytest, coverage, and unittest for unit tests.
 
 You can ensure your contribution adheres to these checks by running `invoke tests` from the CLI.
+The command `invoke build` builds a docker container with all the necessary dependencies (including the redis backend) locally to facilitate the execution of these tests.
 
 # Questions
 Please see the [documentation](https://diffsync.readthedocs.io/en/latest/index.html) for detailed documentation on how to use `diffsync`. For any additional questions or comments, feel free to swing by the [Network to Code slack channel](https://networktocode.slack.com/) (channel #networktocode). Sign up [here](http://slack.networktocode.com/)