Add alias for last? parameter on environments page

'last?', while usuable as a key in javascript, does not conform to the
rest of the language very well. 'is_last', on the other hand, is more
expected.

app/serializers/deployment_entity.rb

@@ -22,6 +22,8 @@ class DeploymentEntity < Grape::Entity
   expose :deployed_at
   expose :tag
   expose :last?
+  expose :last?, as: :is_last
+
   expose :deployed_by, as: :user, using: UserEntity
 
   expose :deployable, if: -> (deployment) { deployment.deployable.present? } do |deployment, opts|

app/serializers/deployment_serializer.rb

@@ -4,7 +4,7 @@ class DeploymentSerializer < BaseSerializer
   entity DeploymentEntity
 
   def represent_concise(resource, opts = {})
-    opts[:only] = [:iid, :id, :sha, :created_at, :deployed_at, :tag, :last?, :id, ref: [:name]]
+    opts[:only] = [:iid, :id, :sha, :created_at, :deployed_at, :tag, :last?, :is_last, :id, ref: [:name]]
     represent(resource, opts)
   end
 end

spec/fixtures/api/schemas/deployment.json

@@ -7,6 +7,7 @@
     "iid",
     "tag",
     "last?",
+    "is_last",
     "ref",
     "id"
   ],
@@ -16,6 +17,7 @@
     "id": { "type": "integer" },
     "iid": { "type": "integer" },
     "last?": { "type": "boolean" },
+    "is_last": { "type": "boolean" },
     "ref": {
       "type": "object",
       "required": [

spec/serializers/deployment_entity_spec.rb

@@ -42,6 +42,10 @@ RSpec.describe DeploymentEntity do
     expect(subject).to include(:deployed_at)
   end
 
+  it 'exposes last? as is_last' do
+    expect(subject).to include(:is_last)
+  end
+
   context 'when deployable is nil' do
     let(:entity) { described_class.new(deployment, request: request, deployment_details: false) }
     let(:deployment) { create(:deployment, deployable: nil, project: project) }