I installed puma gem and when I start rails server by rails s I can see full output:
$ rails s
/Users/serj/.rvm/gems/ruby-2.2.1@email_
If you use foreman or a Procfile, you can add the tail -f log to your Procfile. This is what I use:
# Procfile.dev
web: bundle exec puma -p $PORT
webpack: bin/webpack-dev-server
log: tail -f log/development.log
I then start rails like this:
$> PORT=3000 foreman start -f Procfile.dev
I actually have an alias for this in my .zshrc:
alias railss='PORT=3000 foreman start -f Procfile.dev'
So I can simply start Rails with:
$> railss