Yeah, that's handy I drive on LPG to!
But the functionality is already in the app. It just comes to having an updated list of LPG refueling stations in a correct CSV format.. I don't have it.
Here in the Netherlands it's no problem to get LPG, more than half of all gasstations has it. When i'm on holiday in France, or even worse, Sweden, it's not that common and would be very handy to have such a list.