Allow eloquent builder instance on BelongsTo model field.

Author: yajra

src/Html/Editor/Fields/BelongsTo.php

@@ -3,19 +3,26 @@
 namespace Yajra\DataTables\Html\Editor\Fields;
 
 use Illuminate\Support\Str;
+use Illuminate\Database\Eloquent\Builder;
 
 class BelongsTo extends Select
 {
     /**
-     * @param string $class
+     * @param string|Builder $class
      * @param string $text
      * @param string $id
      * @param string|null $foreign
      * @return \Yajra\DataTables\Html\Editor\Fields\Field|static
      */
     public static function model($class, $text, $id = 'id', $foreign = null)
     {
-        $table   = Str::singular(app($class)->getTable());
+        if ($class instanceof Builder) {
+            $table = $class->getModel()->getTable();
+        } else {
+            $table = app($class)->getTable();
+        }
+
+        $table   = Str::singular($table);
         $foreign = $foreign ?? $table . '_id';
 
         return self::make($foreign, Str::title($table))