title: Include an existing CSS file in custom extjs theme
body: <p>I have an existing CSS file that I would like to include in my ExtJS production build. </p>
  
  <p>I am using a custom theme. I know I can go to MyApp/packages/myCustomTheme/sass/etc/ and use an <code>@import</code> in the all.scss file. But that uses the <code>@import</code> in the production file.</p>
  
  <p>I'm hoping there is a way that I can get my existing CSS file compressed with the rest of my app's CSS.</p>