Set url and dirs explicitly

Fixes #5

wp-config.php.template

@@ -35,6 +35,11 @@ $table_prefix = 'wp_';
 define('WP_HOME', '##APP_ORIGIN');
 define('WP_SITEURL', '##APP_ORIGIN');
 
+define('WP_CONTENT_URL', '##APP_ORIGIN/wp-content');
+define('WP_PLUGIN_URL', '##APP_ORIGIN/wp-content/plugins');
+define('WP_CONTENT_DIR', '/app/data/wp-content');
+define('WP_PLUGIN_DIR', '/app/data/wp-content/plugins');
+
 /*
  http://cmanios.wordpress.com/2014/04/12/nginx-https-reverse-proxy-to-wordpress-with-apache-http-and-different-port/
  http://wordpress.org/support/topic/compatibility-with-wordpress-behind-a-reverse-proxy