Invite using phone number instead of email

I am using devise gem for authenticating users. I modified it a bit to let users signup using a mobile number instead of email id. Which now works as expected.
What I want to do next is inviting users in a project using the phone number. I saw the tutorial for inviting users using the devise_invitable gem. Should I try and modify the gem to use invite on the mobile number or build a custom method?
I am still a bit new to rails, if you can also point me to a resource to enable this use case, that would be really helpful.
Thanks :)