docs: function (pipe) {
          return glob('*/', {cwd: pipe.contentDir})
              .then(function (categories) {
                  categories.forEach(function (category) {
                      // Don't override already defined structures
                      if (pipe.content[category] !== undefined && pipe.content[category].type !== undefined) {
                          return;
                      }
  
                      pipe.content[category] = {
                          type: 'posts'
                      };
                  });
  
                  return Bluebird.resolve(pipe);
              });
      }