Add setup details to documentation

CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 ## Overview
 
-The AdoptOpenJDK API V3 is a Kotlin application (fronted by Swagger and OpenAPI) which makes 
+The AdoptOpenJDK API V3 is a Kotlin application (frontend by Swagger and OpenAPI) which makes 
 calls via the GitHub API in order to retrieve AdoptOpenJDK binaries and metadata.
 
 Since the GitHub API is rate limited we use MongoDB as a caching mechanism.
@@ -21,6 +21,12 @@ eventually merge into `master` for a real Production deployment.
 
 Java 11 is a requirement to build the project.
 
+### Optional Set-up
+
+If you want to use the updater tool to add entries into the database, you need to generate a github token, which can be done here: https://github.com/settings/tokens. It doesn't need any specific permissions. Once you have a token generated, create a file at ~/.adopt_api/token.properties and type token=your-token-here
+
+The production server uses mongodb to store data, however you can also use Fongo. If you would like to install mongodb and are on mac, I used this guide https://zellwk.com/blog/install-mongodb/ which utilises homebrew.
+
 ### Build Tool
 
 We use a Maven Wrapper (mvnw) to ensure that there's a consistent, repeatable build. The