Extend API Issues, MergeRequets, Milestones with iid field

lib/api/entities.rb

@@ -91,15 +91,16 @@ module API
       expose :expires_at, :updated_at, :created_at
     end
 
-    class Milestone < Grape::Entity
-      expose :id
-      expose (:project_id) {|milestone| milestone.project.id}
+    class ProjectEntity < Grape::Entity
+      expose :id, :iid
+      expose (:project_id) { |entity| entity.project.id }
+    end
+
+    class Milestone < ProjectEntity
       expose :title, :description, :due_date, :state, :updated_at, :created_at
     end
 
-    class Issue < Grape::Entity
-      expose :id
-      expose (:project_id) {|issue| issue.project.id}
+    class Issue < ProjectEntity
       expose :title, :description
       expose :label_list, as: :labels
       expose :milestone, using: Entities::Milestone
@@ -107,14 +108,14 @@ module API
       expose :state, :updated_at, :created_at
     end
 
-    class SSHKey < Grape::Entity
-      expose :id, :title, :key, :created_at
+    class MergeRequest < ProjectEntity
+      expose :target_branch, :source_branch, :title, :state, :upvotes, :downvotes
+      expose :author, :assignee, using: Entities::UserBasic
+      expose :source_project_id, :target_project_id
     end
 
-    class MergeRequest < Grape::Entity
-      expose :id, :target_branch, :source_branch, :title, :state, :upvotes, :downvotes
-      expose :target_project_id, as: :project_id
-      expose :author, :assignee, using: Entities::UserBasic
+    class SSHKey < Grape::Entity
+      expose :id, :title, :key, :created_at
     end
 
     class Note < Grape::Entity

spec/requests/api/issues_spec.rb

@@ -42,6 +42,7 @@ describe API::API do
       get api("/projects/#{project.id}/issues/#{issue.id}", user)
       response.status.should == 200
       json_response['title'].should == issue.title
+      json_response['iid'].should == issue.iid
     end
 
     it "should return 404 if issue id not found" do

spec/requests/api/merge_requests_spec.rb

@@ -34,6 +34,7 @@ describe API::API do
       get api("/projects/#{project.id}/merge_request/#{merge_request.id}", user)
       response.status.should == 200
       json_response['title'].should == merge_request.title
+      json_response['iid'].should == merge_request.iid
     end
 
     it "should return a 404 error if merge_request_id not found" do

spec/requests/api/milestones_spec.rb

@@ -30,6 +30,7 @@ describe API::API do
       get api("/projects/#{project.id}/milestones/#{milestone.id}", user)
       response.status.should == 200
       json_response['title'].should == milestone.title
+      json_response['iid'].should == milestone.iid
     end
 
     it "should return 401 error if user not authenticated" do