I have a Custom module Where i managed to override the `web_gantt`'s GanttView and change the gantt to my own gantt that has a few more improvements that i need. 

But this isn't very good for all the Gantt views so i need a new view type which i  can use like any other view via XML.

<gantt date_start="date_start" date_stop="date_end" string="Tervezés"> </gantt>

<planner date_start="date_start" date_stop="date_end" string="Tervezés"> </planner>

SO how can i do this?