move resource_model method for ResourceModel concern to improve code reuse

app/controllers/concerns/resource_model.rb

+module ResourceModel
+  extend ActiveSupport::Concern
+
+  protected
+
+  def resource_model
+    resource, id = request.path.split('/')[2, 3]
+    resource_model = resource.singularize.classify.constantize
+    resource_model.find(id)
+  end
+
+end

app/controllers/v1/activities_controller.rb

 class V1::ActivitiesController < ApplicationController
-  before_action :authenticate_user!, only: [:my_activities]
+  include ::ResourceModel
+  before_action :authenticate_user!
 
   # GET v1/activities
   # GET v1/activities.json
@@ -15,12 +16,6 @@ class V1::ActivitiesController < ApplicationController
 
   private
 
-  def resource_model
-    resource, id = request.path.split('/')[2, 3]
-    resource_model = resource.singularize.classify.constantize
-    resource_model.find(id)
-  end
-
   def activities(object)
     condition = '(owner_type = :type AND owner_id = :id) OR (recipient_type = :type AND recipient_id = :id)'
     PublicActivity::Activity.order('created_at DESC').where(condition, {type: object.class.to_s, id: object.id}).all

app/controllers/v1/versions_controller.rb

 class V1::VersionsController < ApplicationController
+  include ::ResourceModel
 
   # GET v1/learning_objects/1/versions
   # GET v1/learning_objects/1/versions.json
@@ -13,6 +14,7 @@ class V1::VersionsController < ApplicationController
     render json: resource
   end
 
+  # POST /learning_objects/1/versions/234/checkout
   def checkout
     resource = PaperTrail::Version.find(params[:id]).reify
     if resource.save
@@ -22,12 +24,4 @@ class V1::VersionsController < ApplicationController
     end
   end
 
-  private
-
-  def resource_model
-    resource, id = request.path.split('/')[2, 3]
-    resource_model = resource.singularize.classify.constantize
-    resource_model.find(id)
-  end
-
 end