Remove .ruby-version and .rvmrc

Do we need these?

Rvm should be able to handle which ruby version to use through
the Gemfile.

"RVM used your Gemfile for selecting Ruby, it is all fine - Heroku does
that too,

you can ignore these warnings with 'rvm rvmrc warning ignore
/Users/tomas/Projects/barsoom/gridlook/Gemfile'.
To ignore the warning for all files run 'rvm rvmrc warning ignore
allGemfiles'."