∴ rvm migrate from to

Efficiently moves the gems from one ruby to another.
Like 'rvm gemset copy' but removes the gems from the source
ruby afterwards and runs it against all gemsets for a given
ruby.

Examples:

To migrate all gemsets from rc2 of 1.9.2 to the first release, p0,
you'd run:

  ∴ rvm migrate 1.9.2-rc2 1.9.2-p0