DEV: Update plugin to match latest guidelines (#448)

This commit updates the plugin to follow the latest guidelines, as
shown in discourse-plugin-skeleton, removing the explicit require calls
and using config/routes.rb for defining all routes.

config/routes.rb

@@ -9,3 +9,25 @@ DiscourseAssign::Engine.routes.draw do
   get "/members/:group_name" => "assign#group_members"
   get "/user-menu-assigns" => "assign#user_menu_assigns"
 end
+
+Discourse::Application.routes.append do
+  mount ::DiscourseAssign::Engine, at: "/assign"
+
+  get "topics/private-messages-assigned/:username" => "list#private_messages_assigned",
+      :as => "topics_private_messages_assigned",
+      :constraints => {
+        username: ::RouteFormat.username,
+      }
+  get "/topics/messages-assigned/:username" => "list#messages_assigned",
+      :constraints => {
+        username: ::RouteFormat.username,
+      },
+      :as => "messages_assigned"
+  get "/topics/group-topics-assigned/:groupname" => "list#group_topics_assigned",
+      :constraints => {
+        username: ::RouteFormat.username,
+      },
+      :as => "group_topics_assigned"
+  get "/g/:id/assigned" => "groups#index"
+  get "/g/:id/assigned/:route_type" => "groups#index"
+end

lib/discourse_assign/engine.rb

@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+
+module ::DiscourseAssign
+  class Engine < ::Rails::Engine
+    engine_name PLUGIN_NAME
+    isolate_namespace DiscourseAssign
+  end
+end

plugin.rb

@@ -14,67 +14,29 @@ register_asset "stylesheets/mobile/assigns.scss", :mobile
 
 %w[user-plus user-times group-plus group-times].each { |i| register_svg_icon(i) }
 
-require_relative "app/models/assign_mailer_site_settings.rb"
-require_relative "app/models/remind_assigns_frequency_site_settings.rb"
-require_relative "lib/validators/assign_statuses_validator.rb"
+module ::DiscourseAssign
+  PLUGIN_NAME = "discourse-assign"
+end
+
+require_relative "lib/discourse_assign/engine"
+require_relative "lib/validators/assign_statuses_validator"
 
 after_initialize do
-  module ::DiscourseAssign
-    PLUGIN_NAME = "discourse-assign"
-
-    class Engine < ::Rails::Engine
-      engine_name DiscourseAssign::PLUGIN_NAME
-      isolate_namespace DiscourseAssign
-    end
-  end
-
-  require_relative "app/controllers/discourse_assign/assign_controller.rb"
-  require_relative "app/mailers/assign_mailer.rb"
-  require_relative "app/models/assign_mailer_site_settings.rb"
-  require_relative "app/models/assignment.rb"
-  require_relative "app/models/remind_assigns_frequency_site_settings.rb"
-  require_relative "app/serializers/assigned_group_serializer.rb"
-  require_relative "app/serializers/assigned_topic_serializer.rb"
-  require_relative "app/serializers/group_user_assigned_serializer.rb"
-  require_relative "config/routes.rb"
-  require_relative "jobs/regular/assign_notification.rb"
-  require_relative "jobs/regular/remind_user.rb"
-  require_relative "jobs/regular/unassign_notification.rb"
-  require_relative "jobs/scheduled/enqueue_reminders.rb"
-  require_relative "lib/assigner.rb"
-  require_relative "lib/discourse_assign/discourse_calendar.rb"
-  require_relative "lib/discourse_assign/group_extension.rb"
-  require_relative "lib/discourse_assign/helpers.rb"
-  require_relative "lib/discourse_assign/list_controller_extension.rb"
-  require_relative "lib/discourse_assign/post_extension.rb"
-  require_relative "lib/discourse_assign/topic_extension.rb"
-  require_relative "lib/discourse_assign/web_hook_extension.rb"
-  require_relative "lib/pending_assigns_reminder.rb"
-  require_relative "lib/random_assign_utils.rb"
-  require_relative "lib/topic_assigner.rb"
-  require_relative "lib/validators/assign_statuses_validator.rb"
-
-  Discourse::Application.routes.append do
-    mount ::DiscourseAssign::Engine, at: "/assign"
-
-    get "topics/private-messages-assigned/:username" => "list#private_messages_assigned",
-        :as => "topics_private_messages_assigned",
-        :constraints => {
-          username: ::RouteFormat.username,
-        }
-    get "/topics/messages-assigned/:username" => "list#messages_assigned",
-        :constraints => {
-          username: ::RouteFormat.username,
-        },
-        :as => "messages_assigned"
-    get "/topics/group-topics-assigned/:groupname" => "list#group_topics_assigned",
-        :constraints => {
-          username: ::RouteFormat.username,
-        },
-        :as => "group_topics_assigned"
-    get "/g/:id/assigned" => "groups#index"
-    get "/g/:id/assigned/:route_type" => "groups#index"
-  end
+  require_relative "app/jobs/regular/assign_notification"
+  require_relative "app/jobs/regular/remind_user"
+  require_relative "app/jobs/regular/unassign_notification"
+  require_relative "app/jobs/scheduled/enqueue_reminders"
+  require_relative "lib/assigner"
+  require_relative "lib/discourse_assign/discourse_calendar"
+  require_relative "lib/discourse_assign/group_extension"
+  require_relative "lib/discourse_assign/helpers"
+  require_relative "lib/discourse_assign/list_controller_extension"
+  require_relative "lib/discourse_assign/post_extension"
+  require_relative "lib/discourse_assign/topic_extension"
+  require_relative "lib/discourse_assign/web_hook_extension"
+  require_relative "lib/pending_assigns_reminder"
+  require_relative "lib/random_assign_utils"
+  require_relative "lib/topic_assigner"
 
   reloadable_patch do |plugin|
     Group.class_eval { prepend DiscourseAssign::GroupExtension }