Add newest_version placeholders

Author: bruceadams

app/models/crate.js

@@ -8,6 +8,7 @@ export default DS.Model.extend({
   created_at: DS.attr('date'),
   updated_at: DS.attr('date'),
   max_version: DS.attr('string'),
+  newest_version: DS.attr('string'),
 
   description: DS.attr('string'),
   homepage: DS.attr('string'),

mirage/factories/crate.js

@@ -15,6 +15,7 @@ export default Factory.extend({
   homepage: () => faker.internet.url(),
   repository: () => faker.internet.url(),
   max_version: () => faker.system.semver(),
+  newest_version: () => faker.system.semver(),
 
   created_at: () => faker.date.past(),
   updated_at() {

mirage/serializers/crate.js

@@ -14,6 +14,7 @@ export default BaseSerializer.extend({
     'keywords',
     'links',
     'max_version',
+    'newest_version',
     'name',
     'repository',
     'updated_at',