Modify .rvmrc to create gemset if it doesn't exist

Updated the .rvmrc to create the fulcrum_api gemset if it doesn't exist.

Currently I get the error
`Gemset 'fulcrum_api' does not exist, 'rvm gemset create fulcrum_api' first, or append '--create'.` 
when I `cd` to the folder for the first time on a new machine, since I hadn't created the gemset.

This fixes that error issue - making the gem ready to use right away for other new developers.