Hi,
Im not aware of any steps, plugins or pre-build to access read/write firebase, but you may have at least 2 ways to accomplish that.
1 - REST API (just make the calls using a REST step)
https://firebase.google.com/docs/reference/rest/database/#section-query-parameters
2 - Java API (under development) - https://github.com/bane73/firebase4j/blob/master/src/net/thegreshams/firebase4j/demo/Demo.java;
Rest api seens to be the safe and easie way to go.