title: How to authorize the google-api-ruby-client?
body: <p>I'm working to get the google-api-ruby-client gem working following the basic usage example here: Basic usage</p>
  
  <pre><code>require 'google/apis/drive_v2'
  
  Drive = Google::Apis::DriveV2 # Alias the module
  drive = Drive::DriveService.new
  drive.authorization = ... # See Googleauth or Signet libraries
  
  # Search for files in Drive (first page only)
  files = drive.list_files(q: "title contains 'finances'")
  files.items.each do |file|
    puts file.title
  end
  </code></pre>
  
  <p>Where I'm stuck is <code>drive.authorization</code>. I have an authorized token already for the user via the gem omniauth-google-oauth2. How do I use that token with google-api-ruby-client?</p>