code: function Blog(loader, options) {
      this.slugs = {};
      this.ids = {};
      this.posts = [];
      this.length = 0;
      options = options || {};
      if (typeof loader === 'string') {
          loader = new FileSystemLoader(loader, options);
      } else if (Array.isArray(loader)) {
          loader = new ArrayLoader(loader);
      }
      var self = this;
      loader.on('error', function (err) {
          self.emit('error', err);
      });
      loader.on('load', this.onLoad.bind(this));
      loader.on('new_post', this.onNewPost.bind(this));
      loader.on('updated_post', this.onUpdatedPost.bind(this));
      loader.on('removed_post', this.onRemovedPost.bind(this));
  }
docs: Create a new blog.
  
  @param {Loader|Array|String} loader
  @param {Object} options (optional)