Ensuring that the output doesn't get buffered is particularly
relevant once the server is started because Dredd relies on it.
In order to be able to start programatically a server in
the best conditions, that step should be part of the server
starting procedure.

Using a buffered output while loading the hookfiles, on the other
hand poses no particular problem.

Unless I'm wrong, declaring bundler as a dependency is superfluous
(e.g. its version is not locked in the Gemfile).