Allow forUpdate for any model

no issue

- this was only supported for the Post Model until now
- locking should be possible for every resource depending on the use case

core/server/models/base/index.js

@@ -125,6 +125,25 @@ ghostBookshelf.Model = ghostBookshelf.Model.extend({
         return validation.validateSchema(this.tableName, this.toJSON());
     },
 
+    /**
+     * http://knexjs.org/#Builder-forUpdate
+     * https://dev.mysql.com/doc/refman/5.7/en/innodb-locking-reads.html
+     *
+     * Lock target collection/model for further update operations.
+     * This avoids collisions and possible content override cases.
+     */
+    onFetching: function onFetching(model, columns, options) {
+        if (options.forUpdate && options.transacting) {
+            options.query.forUpdate();
+        }
+    },
+
+    onFetchingCollection: function onFetchingCollection(model, columns, options) {
+        if (options.forUpdate && options.transacting) {
+            options.query.forUpdate();
+        }
+    },
+
     /**
      * Adding resources implies setting these properties on the server side
      * - set `created_by` based on the context
@@ -369,7 +388,7 @@ ghostBookshelf.Model = ghostBookshelf.Model.extend({
      */
     permittedOptions: function permittedOptions() {
         // terms to whitelist for all methods.
-        return ['context', 'include', 'transacting', 'importing'];
+        return ['context', 'include', 'transacting', 'importing', 'forUpdate'];
     },
 
     /**

core/server/models/post.js

@@ -56,27 +56,6 @@ Post = ghostBookshelf.Model.extend({
         return this.updateTags(model, response, options);
     },
 
-    /**
-     * http://knexjs.org/#Builder-forUpdate
-     * https://dev.mysql.com/doc/refman/5.7/en/innodb-locking-reads.html
-     *
-     * Lock target collection/model for further update operations.
-     * This avoids collisions and possible content override cases.
-     *
-     * `forUpdate` is only supported for posts right now
-     */
-    onFetching: function onFetching(model, columns, options) {
-        if (options.forUpdate && options.transacting) {
-            options.query.forUpdate();
-        }
-    },
-
-    onFetchingCollection: function onFetchingCollection(model, columns, options) {
-        if (options.forUpdate && options.transacting) {
-            options.query.forUpdate();
-        }
-    },
-
     onUpdated: function onUpdated(model) {
         model.statusChanging = model.get('status') !== model.updated('status');
         model.isPublished = model.get('status') === 'published';
@@ -624,10 +603,9 @@ Post = ghostBookshelf.Model.extend({
             // whitelists for the `options` hash argument on methods, by method name.
             // these are the only options that can be passed to Bookshelf / Knex.
             validOptions = {
-                findOne: ['columns', 'importing', 'withRelated', 'require', 'forUpdate'],
+                findOne: ['columns', 'importing', 'withRelated', 'require'],
                 findPage: ['page', 'limit', 'columns', 'filter', 'order', 'status', 'staticPages'],
-                findAll: ['columns', 'filter', 'forUpdate'],
+                findAll: ['columns', 'filter']
-                edit: ['forUpdate']
             };
 
         // The post model additionally supports having a formats option