How to persists noise profile registration? (DT forgets noise profile once i close DT)

I am using darktable 2.6 on Ubuntu 18.04.

Noise profile for Nikon Z7 does not persist. When I open darktable, Denoise Profile will not list Nikon Z7, instead it says “generic”. Then I have to register the Noise profile using following command
darktable --noiseprofiles /pathTo/presets.json

After that Denoise Profile will list Nikon Z7. If I close and reopen darktable, Denoise Profile will get lost. I have to reregister the noise profile once more.

How can I persist the Noise profile?
Where should I copy the present.json?
Should I run registration as sudo?

Thanks

darktable stores noise profiles in an external json file. This file can be found in $DARKTABLE/share/darktable/noiseprofile.json where $DARKTABLE represents the darktable installation directory.

From https://www.darktable.org/usermanual/en/correction_group.html#denoise_profiled

You need to add your json bits there. However, it might be over written the next time DT updates. If you haven’t submitted this to the project for inclusion, you really should.

Thanks,
Had to copy it to /usr/share/darktable/noiseprofiles.json