title: Monitoring sub-task for grunt-contrib-watch
body: <p>I have the following Gruntfile.coffee. I am monitoring the watch task as shown below to see file changes and then compile the changed file to coffee-script.    </p>
  
  <pre><code># Watch task
  watch:
   coffee:
    files: ['client/**/*.coffee','server/**/*/.coffee']
    options:
     nospawn: true
     livereload: true
  
  # Watch changed files
  grunt.event.on 'watch', (action, filepath) -&gt;
   cwd = 'client/'
   filepath = filepath.replace(cwd,'')
   grunt.config.set('coffee',
    changed:
     expand: true
     cwd: cwd
     src: filepath
     dest: 'client-dist/'
     ext: '.js'
   )
   grunt.task.run('coffee:changed')
  </code></pre>
  
  <p>However, I would like to add another watch task to copy files over that are not coffee files. How would I monitor these changes?</p>
  
  <p>I thought of doing </p>
  
  <pre><code># Watch copy task
  grunt.event.on 'watch:copy', (action,filepath) -&gt; ...
  # Watch coffee task
  grunt.event.on 'watch:coffee', (action,filepath) -&gt; ...
  </code></pre>
  
  <p>but that doesn't seem to work. Ideas?</p>