Add order on topic index.

app/controllers/communities_controller.rb

@@ -1,6 +1,8 @@
 class CommunitiesController < ApplicationController
 
-  before_action :set_community, :load_topics, only: :show
+  before_action :set_order, :set_community, :load_topics, only: :show
+
+  has_orders %w{newest most_commented oldest}, only: :show
 
   skip_authorization_check
 
@@ -9,11 +11,15 @@ class CommunitiesController < ApplicationController
 
   private
 
+  def set_order
+    @order = params[:order].present? ? params[:order] : "newest"
+  end
+
   def set_community
     @community = Community.find(params[:id])
   end
 
   def load_topics
-    @topics = @community.topics.page(params[:page])
+    @topics = @community.topics.send("sort_by_#{@order}").page(params[:page])
   end
 end

app/models/topic.rb

@@ -9,6 +9,10 @@ class Topic < ActiveRecord::Base
 
   after_create :associate_comment
 
+  scope :sort_by_newest, -> { order(created_at: :desc) }
+  scope :sort_by_oldest, -> { order(created_at: :asc) }
+  scope :sort_by_most_commented,   -> { reorder(comments_count: :desc) }
+
   private
 
   def associate_comment

app/views/topics/_topics.html.erb

@@ -1,22 +1,6 @@
-<div class="row column">
-  <div class="order">
-    <div class="wide-order-selector small-12 medium-8">
-      <form>
-        <div class="small-12 medium-8 float-left">
-          <label for="order-selector-participation">
+<div class="order">
   Ordenar por:
-          </label>
-        </div>
-
-        <div class="small-12 medium-4 float-left">
-          <select class="js-location-changer js-order-selector select-order">
-            <option>Value 1</option>
-            <option>Value 2</option>
-          </select>
-        </div>
-      </form>
-    </div>
-  </div>
+  <%= render 'shared/wide_order_selector', i18n_namespace: "topics" %>
 </div>
 
 <% if topics.any? %>