gistfile1.txt

tim@rocketman:autoprotocol-dsl (master #)$ ls
Gemfile      Gemfile.lock sketch.rb
tim@rocketman:autoprotocol-dsl (master #)$ cat Gemfile
source 'https://rubygems.org'
gem 'docile'
tim@rocketman:autoprotocol-dsl (master #)$ bundle check
The Gemfile's dependencies are satisfied
tim@rocketman:autoprotocol-dsl (master #)$ head sketch.rb 
require 'json'

require 'docile'

#class Protocol
#  def initialize(refs = nil, steps = nil)
#    @refs = refs or []
#    @steps = steps or []
#  end

tim@rocketman:autoprotocol-dsl (master #)$ bundle exec ruby sketch.rb 
Could not find docile-1.1.5 in any of the sources
Run `bundle install` to install missing gems.