title: How to import sbt pack plugin to project
body: <p>I follow the <a href="https://github.com/xerial/sbt-pack" rel="nofollow">sbt-pack</a> link to import the plugin. I did:</p>
  
  <ol>
  <li><p>add a line <code>addSbtPlugin("org.xerial.sbt" % "sbt-pack" % "0.7.5")</code> to <code>plugins.sbt</code> under my project root directory.</p></li>
  <li><p>add a line <code>packAutoSettings</code> to the very top of <code>build.sbt</code> file under project root directory</p></li>
  </ol>
  
  <p>then I run sbt to start the console, it said:
  <code>
  error: not found: value packAutoSettings
  </code></p>
  
  <p>Also when I run sbt plugins, I don't see the new <code>sbt-pack</code> plugin shown on the list.</p>
  
  <p>I also tried to create a file called pack.sbt and add content like:
  <code>
  pack.settings
  addSbtPlugin("org.xerial.sbt" % "sbt-pack" % "0.7.5")
  </code>
  but it doesn't work as well.</p>