We were installing RVM every time we were deploying, which meant
deployments took a few extra seconds and generated a lot of unneeded
output even when we didn't have to update Ruby.
We need to update RVM when a new Ruby version needs to be installed
(otherwise we could be asking RVM to install a Ruby version which the
current RVM version cannot handle), but in every other case we're fine
using the already installed RVM version.
We're also considering the case where the RVM command is not available.
Even though the CONSUL installer installs RVM, some people might prefer
to install it through Capistrano.
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