Add filter dropdown to tag page

app/controllers/projects/tags_controller.rb

@@ -6,7 +6,8 @@ class Projects::TagsController < Projects::ApplicationController
   before_action :authorize_admin_project!, only: [:destroy]
   def index
-    sorted = VersionSorter.rsort(@repository.tag_names)
+    @sort = params[:sort]
+    sorted = tags_sorted_by(@sort)
     @tags = Kaminari.paginate_array(sorted).page(params[:page])
     @releases = project.releases.where(tag: @tags)
   end
@@ -41,4 +42,19 @@ class Projects::TagsController < Projects::ApplicationController
       format.js
     end
   end
+
+  private
+
+  def tags_sorted_by(value)
+    default_sort = VersionSorter.rsort(@repository.tag_names)
+
+    case value
+    when 'recently_released'
+      default_sort
+    when 'last_released'
+      VersionSorter.sort(@repository.tag_names)
+    else
+      default_sort
+    end
+  end
 end

app/helpers/sorting_helper.rb

@@ -44,6 +44,14 @@ module SortingHelper
     'Last created'
   end
+  def sort_title_recently_released
+    'Last released'
+  end
+
+  def sort_title_oldest_released
+    'Oldest released'
+  end
+
   def sort_title_milestone_soon
     'Milestone due soon'
   end

app/views/projects/tags/index.html.haml

@@ -8,6 +8,21 @@
       = link_to new_namespace_project_tag_path(@project.namespace, @project), class: 'btn btn-create new-tag-btn' do
         = icon('plus')
         New tag
+       
+      .dropdown.inline
+        %button.dropdown-toggle.btn{type: 'button', 'data-toggle' => 'dropdown'}
+          %span.light
+          - if @sort.present?
+            = @sort.humanize
+          - else
+            Filter
+          %b.caret
+        %ul.dropdown-menu.dropdown-menu-align-right
+          %li
+            = link_to namespace_project_tags_path(sort: 'recently_released') do
+              = sort_title_recently_released
+            = link_to namespace_project_tags_path(sort: 'last_released') do
+              = sort_title_oldest_released
   .oneline
     Tags give the ability to mark specific points in history as being important