title: How to use gulp-watch?
body: <p>What is the proper way to use gulp-watch plugin?</p>
  
  <pre><code>...
  var watch = require('gulp-watch');
  
  function styles() {
    return gulp.src('app/styles/*.less')
      .pipe(watch('app/styles/*.less'))
      .pipe(concat('main.css'))
      .pipe(less())
      .pipe(gulp.dest('build'));
  }
  
  gulp.task('styles', styles);
  </code></pre>
  
  <p>I don't see any results when run <code>gulp styles</code>.</p>