[codyb]

I don't have as detailed an answer as several of the other commenters here, but as someone in the job market at the moment I see a decent amount of Rails work floating around.

Another framework that seems to have been burgeoning in enthusiasm lately is Phoenix, built in Elixir which is a Ruby like syntax. The neat thing there is that it introduces a ton of interesting OTP concepts borrowed from Erlang (both Erlang and Elixir compile down to bytecode for the same virtual machine, the beam).