add delete post route

app/templates/posts/delete.html

@@ -0,0 +1,16 @@
+{%- from 'common/macros.html' import subheader -%}
+{%- from 'common/macros.html' import full_post with context -%}
+{%- extends 'base.html' -%}
+{%- block title -%}deleting a post{%- endblock -%}
+{%- block content -%}
+  {%- call() subheader("Delete post", "Are you sure you want to delete this post? This action can not be undone.") -%}
+  <form method="POST">
+    <fieldset class="plank minimal even no-shadow thread-actions">
+        <legend>Please confirm</legend>
+        <a href="{{get_post_url(post.id, _anchor=true)}}" class="linkbutton">Cancel</a>
+        <input type="submit" value="Delete" class="critical">
+    </fieldset>
+  </form>
+  {%- endcall -%}
+  <div class="post plank">{{- full_post(post=post, show_toolbar=false, show_reactions=false) -}}</div>
+{%- endblock -%}