Add instruction to include rjenkinsjr repo in POM

src/site/markdown/devs.md

@@ -23,6 +23,7 @@ ${project.name} for Plugin Developers
 
 If you wish to use [SLF4J](http://slf4j.org) in your Bukkit plugin, or if your plugin has a dependency on a library that uses SLF4J:
 
++ Reference the [rjenkinsjr Maven2 Repository](https://github.com/rjenkinsjr/maven2) in your POM.
 + [Shade](https://maven.apache.org/plugins/maven-shade-plugin/usage.html) SLF4Bukkit into your plugin project:
 
 ```xml