title: Add task dependency to existing Gradle task
body: <p>I'm going to lose my mind about this. I have a <code>build.gradle</code> file that looks something like:</p>
  
  <pre><code>apply plugin: 'idea'
  task blah{
    // do something
  }
  idea{
    // some stuff
    dependsOn blah
  }
  </code></pre>
  
  <p>and I'm getting this:</p>
  
  <pre><code>Could not find method dependsOn() for arguments [task ':blah'] on root project ...
  </code></pre>
  
  <p>I can't figure out what the right syntax is. Any help?</p>