Added default scope for OpenLDAP users

A new default scope has been added for OpenLDAP users requring `memberof` access for authenticated users.

Closes #433

Author: stevebauman

src/Scopes/MemberOfScope.php

@@ -0,0 +1,35 @@
+<?php
+
+namespace Adldap\Laravel\Scopes;
+
+use Adldap\Query\Builder;
+
+class MemberOfScope implements ScopeInterface
+{
+    /**
+     * {@inheritdoc}
+     */
+    public function apply(Builder $builder)
+    {
+        $builder->select($this->getSelectedAttributes($builder));
+    }
+
+    /**
+     * Retrieve the attributes to select for the scope.
+     *
+     * This merges the current queries selected attributes so we
+     * don't overwrite any other scopes selected attributes.
+     *
+     * @param Builder $builder
+     *
+     * @return array
+     */
+    protected function getSelectedAttributes(Builder $builder)
+    {
+        $selected = $builder->getSelects();
+
+        return array_merge($selected, [
+            $builder->getSchema()->memberOf(),
+        ]);
+    }
+}