Move Group from Peatio to Barong

[martianatwork]

Peatio has Trading Fee groups, we are using group in members table to identify it.

I believe groups should be available in barong instead of peatio.

This way we can reuse group in multiple applications as we are using barong to authenticate users.

In peatio we can keep everything as it is just add group column in barong and move group change API to barong instead of peatio

[ec]

Hi @martianatwork . That might be a good idea, but its not scheduled in nearest plans

[martianatwork]

@ec Let me know if I can create a PR to add this feature.

[ec]

@martianatwork feel free to try) Lets see if you can fit in the general plan