code: function chain(tasks) {
        return function() {
          var pipeline = fullPipeline();
  
          _.each(tasks, function(task) {
            pipeline = pipeline.pipe(task.callback(options)());
          });
  
          return pipeline;
        };
      }
docs: Create the pipeline chain for the provided tasks.
  
  @name chain
  @param {Array} tasks - The list of task objects to chain callbacks.
  @return {Function} - A function that when invoked, runs the entire pipeline and returns the vinyl stream.