Started styling the app and have got editing posts working.

templates/posts/new.html

@@ -0,0 +1,13 @@
+{{- $postTarget := printf "/sites/%v/posts" .site.ID -}}
+{{- if .post.ID -}}
+    {{- $postTarget = printf "/sites/%v/posts/%v" .site.ID .post.ID -}}
+{{- end -}}
+<form method="post" action="{{$postTarget}}" class="post-form">
+    <input name="title" placeholder="Title" value="{{.post.Title}}">
+
+    <textarea name="body">{{.post.Body}}</textarea>
+
+    <div class="bottom-bar">
+        <input type="submit" value="Post">
+    </div>
+</form>