creates a link function
      return function(scope, element, attrs) {
        scope.$watch(
          function(scope) {
             // watch the 'compile' expression for changes
            return scope.$eval(attrs.compile);
          },
          function(value) {
            // when the 'compile' expression changes
            // assign it into the current DOM
            element.html(value);

            // compile the new DOM and link it to the current
            // scope.
            // NOTE: we onl