Started working on the frontend

- Added the new post frontend
- Hooked up publishing of posts to the site publisher
- Added an site exporter as a publishing target

sql/queries/posts.sql

@@ -1,6 +1,9 @@
 -- name: SelectPostsOfSite :many
 SELECT * FROM posts WHERE site_id = ? ORDER BY created_at DESC LIMIT 10;
 
+-- name: SelectPostByGUID :one
+SELECT * FROM posts WHERE guid = ? LIMIT 1;
+
 -- name: InsertPost :one
 INSERT INTO posts (
     site_id,
@@ -11,4 +14,12 @@ INSERT INTO posts (
     created_at,
     published_at
 ) VALUES (?, ?, ?, ?, ?, ?, ?)
-RETURNING id;
+RETURNING id;
+
+-- name: UpdatePost :exec
+UPDATE posts SET
+    title = ?,
+    body = ?,
+    slug = ?,
+    published_at = ?
+WHERE id = ?;