How to run grunt server in dist directory instead of app directory?

The very short answer is

grunt serve:dist

That works with my yeoman-generated Gruntfile.js which contains:

  grunt.registerTask('serve', function (target) {
    if (target === 'dist') {
      return grunt.task.run(['build', 'connect:dist:keepalive']);
    }

    grunt.task.run([
      'clean:server',
      'bower-install',
      'concurrent:server',
      'autoprefixer',
      'connect:livereload',
      'watch'
    ]);
  });