Add prototype of pipelines serializer with pagination

app/controllers/projects/pipelines_controller.rb

@@ -18,6 +18,7 @@ class Projects::PipelinesController < Projects::ApplicationController
          render json: {
            pipelines: PipelineSerializer
              .new(project: @project, user: @current_user)
+             .with_pagination(request, response)
              .represent(@pipelines),
            updated_at: Time.now.utc,
            count: {

app/serializers/pipeline_serializer.rb

 class PipelineSerializer < BaseSerializer
   entity PipelineEntity
+  include API::Helpers::Pagination
+  Struct.new('Pagination', :request, :response)
+
+  def with_pagination(request, response)
+    tap { @pagination = Struct::Pagination.new(request, response) }
+  end
+
+  def paginate?
+    defined?(@pagination)
+  end
+
+  def represent(resource, opts = {})
+    if paginate?
+      super(paginate(resource), opts)
+    else
+      super(resource, opts)
+    end
+  end
+
+  private
+
+  # Methods needed by `API::Helpers::Pagination`
+  #
+  def params
+    @pagination.request.query_parameters
+  end
+
+  def request
+    @pagination.request
+  end
+
+  def header(header, value)
+    @pagination.response.headers[header] = value
+  end
 end