Tests fail when adding otp

[ac74394]

When installing the authentication_zero version that requires OTP_secret, the User fixture should include the following line:

otp_secret: <%= ROTP::Base32.random %>

because, otp_secret is constrained to not be null, and this causes an error when running tests, since the model adds it during the before_validate callback (which are not run when fixtures are created).

Cheers!