Add curated posts page.

Add a curated posts page at /explore/posts/curated. Curated posts are
the most favorited posts by contributor-level users (users with
unlimited upload permissions).

Also add an order:curated tag using for use in regular searches.

app/controllers/explore/posts_controller.rb

@@ -11,6 +11,15 @@ module Explore
       respond_with(@posts)
     end
 
+    def curated
+      @date, @scale, @min_date, @max_date = parse_date(params)
+
+      limit = params.fetch(:limit, CurrentUser.user.per_page)
+      @posts = curated_posts(@min_date, @max_date).paginate(params[:page], limit: limit)
+
+      respond_with(@posts)
+    end
+
     def viewed
       @date, @scale, @min_date, @max_date = parse_date(params)
       @posts = PostViewCountService.new.popular_posts(@date)
@@ -40,5 +49,9 @@ module Explore
     def popular_posts(min_date, max_date)
       Post.where(created_at: min_date..max_date).tag_match("order:score")
     end
+
+    def curated_posts(min_date, max_date)
+      Post.where(created_at: min_date..max_date).tag_match("order:curated")
+    end
   end
 end