Bugfix: Fix major security issue causing unwanted pushes to Rubygems

Previously it was accidentally pushing gems to Rubygems if there was no 'fury'
remote.  This can obviously cause problems if we are working in a gem which we
do _not_ want to public but we _also_ forget to create a 'fury' remote.

Now, we require that there be a file called `.gemrc` containing the content
'public' to explicitly state that the gem should be pushed publicly.

--------------------------------------------------------------------------------
Change-Id:     I8a2992825ec1a2169db6219a847f86eb0ed64565
Signed-off-by: Jeff Felchner <accounts+git@thekompanee.com>