title: Custom Variable in Fastlane Script
body: <p>Sorry for such a newbie question, but I'm very confused on how to write a Fastlane script outside of using the supplied methods.</p>
  
  <p>What I'm looking to do is create a variable called <code>message</code>, that can be passed to the <code>after_all</code> function, so when I post to Slack, each lane can have it's own custom message:</p>
  
  <pre><code>put message # is this how to set a variable?
  lane :alpha do
      # This is what I'd like to do
      message = "[Google Play] Alpha Channel Deployed"
  end
  
  after_all |lane, options| do
      slack(message: message)
  end
  </code></pre>
  
  <p>Can anyone point me in the right direction? I'm so utterly lost on how to create and pass variables that don't come from the command line in a Fastfile script</p>