Display basic info in PSM once an email has been sent

ghost/admin/app/models/email.js

@@ -13,9 +13,9 @@ export default Model.extend({
     submittedAtUTC: attr('moment-utc'),
     uuid: attr('string'),
 
-    createdAtUTC: attr('string'),
+    createdAtUTC: attr('moment-utc'),
     createdBy: attr('string'),
-    updatedAtUTC: attr('string'),
+    updatedAtUTC: attr('moment-utc'),
     updatedBy: attr('string'),
 
     post: belongsTo('post')

ghost/admin/app/serializers/email.js

@@ -0,0 +1,10 @@
+/* eslint-disable camelcase */
+import ApplicationSerializer from 'ghost-admin/serializers/application';
+
+export default ApplicationSerializer.extend({
+    attrs: {
+        createdAtUTC: {key: 'created_at'},
+        updatedAtUTC: {key: 'updated_at'},
+        submittedAtUTC: {key: 'submitted_at'}
+    }
+});

ghost/admin/app/templates/components/gh-post-settings-menu/email.hbs

@@ -5,12 +5,21 @@
 </div>
 
 <div class="settings-menu-content settings-menu-email">
+    {{#if post.email}}
+        {{!-- Mail has already been sent --}}
+        <p>Subject: {{this.post.email.subject}}</p>
+        <p>Status: {{this.post.email.status}}</p>
+        <p>Sent on: {{gh-format-post-time this.post.email.createdAtUTC}}</p>
+        <p>Sent to {{pluralize this.post.email.emailCount "member"}}</p>
+    {{else}}
+        {{!-- Mail not sent yet --}}
         {{#if mailgunError}}
             <p class="gh-box gh-box-warning settings-menu-mailgun-warning">
                 {{svg-jar "info" class="w5 h5 fill-yellow nl1"}}
                 You need to configure Mailgun in {{#link-to "settings.labs" data-test-nav="labs"}}Labs → Members settings{{/link-to}} to enable email newsletters.
             </p>
         {{/if}}
+
         <form {{action "discardEnter" on="submit"}}>
             {{#gh-form-group errors=post.errors hasValidated=post.hasValidated property="emailSubject"}}
                 <label for="og-title">Subject</label>
@@ -66,4 +75,5 @@
                 </div>
             </div>
         </form>
+    {{/if}}
 </div>