src/Baum/Node.php
public function children() {
    return $this->hasMany(get_class($this), $this->getParentColumnName())
                ->orderBy($this->getOrderColumnName());
  }
public function children() {
    return $this->hasMany(get_class($this), $this->getParentColumnName())
                ->orderBy($this->getOrderColumnName());
  }
Children relation (self-referential) 1-N.

@return \Illuminate\Database\Eloquent\Relations\HasMany