Add basic subuser listing for servers

app/Repositories/Eloquent/SubuserRepository.php

@@ -3,6 +3,7 @@
 namespace Pterodactyl\Repositories\Eloquent;
 
 use Pterodactyl\Models\Subuser;
+use Illuminate\Support\Collection;
 use Pterodactyl\Exceptions\Repository\RecordNotFoundException;
 use Pterodactyl\Contracts\Repository\SubuserRepositoryInterface;
 
@@ -18,6 +19,22 @@ class SubuserRepository extends EloquentRepository implements SubuserRepositoryI
         return Subuser::class;
     }
 
+    /**
+     * Returns the subusers for the given server instance with the associated user
+     * and permission relationships pre-loaded.
+     *
+     * @param int $server
+     * @return \Illuminate\Support\Collection
+     */
+    public function getSubusersForServer(int $server): Collection
+    {
+        return $this->getBuilder()
+            ->with('user', 'permissions')
+            ->where('server_id', $server)
+            ->get()
+            ->toBase();
+    }
+
     /**
      * Return a subuser with the associated server relationship.
      *