scambra/devise_invitable — comment on commit 9a99ace78e4db281ea07c21f9a82c8dc65121aec
File:  line 0
By dmathieu:

This does not limit to 3.1.

`~> 3.0` means `>= 3.0 && <= 3.x`, where x can be anything.
So this dependency means "any version, in 3.x."