title: How can I create a task for schematics?
body: <p>Angular schematics has some <a href="https://github.com/angular/angular-cli/tree/master/packages/angular_devkit/schematics/tasks" rel="nofollow noreferrer">tasks</a>.
  I want to create my own task to run with the script executor. <a href="https://github.com/angular/angular-cli/blob/b8eee02205329c8f1f1fdc682b3ef04650a34ec9/packages/schematics/angular/migrations/update-7/index.ts#L34" rel="nofollow noreferrer">An example of how angular does this</a>.</p>
  
  <p>At the moment I just spawn predefined tasks at the end of the schematic. </p>