Changing installation steps so it can be installed with Forge 2

The Arquillian can be easily install from the GitHub repository. 
In Forge type: 
	
	addon-install-from-git --url https://github.com/aslakknutsen/plugin-arquillian.git  --branch forge2

If you've built the add-on from the source and have it in your local Maven repository, you can also do it this way: 
	
	addon-install --name arquillian-addon --groupId org.arquillian.forge --version 1.0.0-SNAPSHOT

That's it! The plugin will be downloaded and installed.