Add details to the README for how to generate the otp for a user.
Add details to the README for how to generate the otp for a user.

ShaneWilton/devise-two-factor,yann/devise-two-factor,kesha-antonov/devise-two-factor,civisanalytics/devise-two-factor,tinfoil/devise-two-factor,yann/devise-two-factor,Momozono/Devise-Two-Factor-Test,yann/devise-two-factor,ShaneWilton/devise-two-factor,zlx/devise-two-factor,Momozono/Devise-Two-Factor-Test,ShaneWilton/devise-two-factor,spanner/devise-two-factor,zlx/devise-two-factor,mo-zo/devise-two-factor,dahal/devise-two-factor,spanner/devise-two-factor,Momozono/Devise-Two-Factor-Test,zlx/devise-two-factor,dahal/devise-two-factor,kesha-antonov/devise-two-factor,kesha-antonov/devise-two-factor,spanner/devise-two-factor,dahal/devise-two-factor