public function related($relation, $conditions = array())
	{
		if (is_array($relation))
		{
			foreach ($relation as $k_r => $v_r)
			{
				is_array($v_r) ? $this->related($k_r, $v_r) : $this->related($v_r);
			}
			return $this;
		}

		if (strpos($relation, '.'))
		{
			$rels = explode('.', $relation);
			$model = $this->model;
			foreach ($rels as $r)
			{
				$rel = call_user_func(array($model, 'relations'), $r);
				if (empty($rel))
				{
					throw new \UnexpectedValueException('Relation "'.$r.'" was not found in the model "'.$model.'".');
				}
				$model = $rel->model_to;
			}
		}
		else
		{
			$rel = call_user_func(array($this->model, 'relations'), $relation);
			if (empty($rel))
			{
				throw new \UnexpectedValueException('Relation "'.$relation.'" was not found in the model.');
			}
		}

		$this->relations[$relation] = array($rel, $conditions);

		if ( ! empty($conditions['related']))
		{
			$conditions['related'] = (array) $conditions['related'];
			foreach ($conditions['related'] as $k_r => $v_r)
			{
				is_array($v_r) ? $this->related($relation.'.'.$k_r, $v_r) : $this->related($relation.'.'.$v_r);
			}

			unset($conditions['related']);
		}

		return $this;
	}