install rvm using curl and install ruby code example

Example: rvm install new ruby version

$ ruby -v 						# Check ruby version 
$ rvm install ruby-X.X.X        # Install specific ruby version
$ rvm list						# List ruby versions
$ rvm use ruby-X.X.X			# Choose a version to use
$ rvm use ruby-X.X.X --default  # Set a version as default