Make possible to use custom tags instead of gtfs:id

[KAMI911]

Currently we are using ref:bkk ref:bkv instead of gtfs:id.

Is it possible to use ref:bkk and ref:bkv
https://taginfo.openstreetmap.org/keys/ref%3Abkv
https://taginfo.openstreetmap.org/keys/ref%3Abkk
instead of gtfs:id:
https://taginfo.openstreetmap.org/keys/gtfs%3Aid

[barbeau]

@KAMI911 That's certainly possible! We aren't currently working on this project, but feel free to modify the code yourself to do this. I'd also accept a pull request that allows the user to set the ID tag name as a user setting.