If you're looking for more elegant methods of expressing this in a higher performance runtime, here are two examples.
Erlang: [I+9 || I <- lists:seq(1,5), I >= 3] Haskell: [i+9 | i <- [1..5], i >= 3]
Like go, both Erlang and Haskell both have strong concurrency stories. For an I/O bound server in a production environment, Erlang is a very safe choice.
Compared to these list comprehensions, that ruby example looks unwieldy.