Self-host slack button graphics

templates/integrations/add_slack.html

@@ -11,13 +11,18 @@
     {% if slack_client_id %}
     <div class="jumbotron">
         {% if request.user.is_authenticated %}
-        <p>If your team uses <a href="http://slack.com/">Slack</a>, you can set
+        <p>If your team uses <a href="https://slack.com/">Slack</a>, you can set
         up {% site_name %} to post status updates directly to an appropriate
         Slack channel.</p>
 
         <div class="text-center">
         <a href="https://slack.com/oauth/authorize?scope=incoming-webhook&client_id={{ slack_client_id }}&state={{ state }}">
-            <img alt="Add to Slack" height="40" width="139" src="https://platform.slack-edge.com/img/add_to_slack.png" srcset="https://platform.slack-edge.com/img/add_to_slack.png 1x, https://platform.slack-edge.com/img/[email protected] 2x" />
+            <img
+                alt="Add to Slack"
+                height="40"
+                width="139"
+                src="{% static 'img/integrations/add_to_slack.png' %}"
+                srcset="{% static 'img/integrations/add_to_slack.png' %} 1x, {% static 'img/integrations/[email protected]' %} 2x" />
         </a>
         </div>
 
@@ -111,7 +116,7 @@
     {% else %}
     <h1>Slack</h1>
 
-    <p>If your team uses <a href="http://slack.com/">Slack</a>, you can set
+    <p>If your team uses <a href="https://slack.com/">Slack</a>, you can set
     up {% site_name %} to post status updates directly to an appropriate
     Slack channel.</p>