Описание тега rvm
RVM (Ruby Version Manager) is a command line tool which allows users to install, manage and work with multiple Ruby environments from interpreters to sets of gems easily in the various Unix-like systems (such as Linux and Mac OS X).
Ruby Version Manager (RVM) is written by Wayne E. Seguin. RVM is a tool that lets you have multiple independent Ruby installations on the same machine. You can switch between them using a single command. This is wonderful, because you can experiment with new versions of Ruby while still keeping the old ones on your system.
RVM allows users to deploy each project with its own completely self-contained and dedicated environment — from the specific version of Ruby all the way down to the precise set of required gems to run the application.
A lot of questions are answered on the RVM site.