use image_url for the logo in mails

closes #6013

Changelog.md

@@ -47,6 +47,7 @@
 * Fix liking on single post views when accessed via GUID [#5978](https://github.com/diaspora/diaspora/pull/5978)
 * Only return the current_users participation for post interactions [#6007](https://github.com/diaspora/diaspora/pull/6007)
 * Fix tag rendering in emails [#6009](https://github.com/diaspora/diaspora/pull/6009)
+* Fix the logo in emails [#6013](https://github.com/diaspora/diaspora/pull/6013)
 
 ## Features
 * Hide post title of limited post in comment notification email [#5843](https://github.com/diaspora/diaspora/pull/5843)

app/views/layouts/notifier.html.erb

@@ -28,7 +28,7 @@
   <table cellspacing="0" cellpadding="0" border="0" align="center" width="100%" style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:14px;color:#333;">
     <tr>
       <td style="text-align:center;padding:30px;">
-        <img src="<%=AppConfig.pod_uri.to_s %>assets/branding/logos/logo_small.png" alt="diaspora*" width="59px" height="14px"/>
+        <img src="<%= image_url("branding/logos/logo_small.png") %>" alt="diaspora*" width="59px" height="14px"/>
       </td>
     </tr>
   </table>