Merge pull request #271 from alphagov/additional-password-support

Additional password support

Author: BenSurgisonGDS

docs/v13/documentation/publishing.md

@@ -38,3 +38,21 @@ To set a password, you need to add 2 environment variables where the:
 Older versions of the Prototype Kit require a username - you can [migrate your prototype to version 13](./migrate-an-existing-prototype) or set a username.
 
 Add another environment variable where the `name` is `USERNAME` and the `value` is whatever username you want to use.
+
+## If you want to create additional passwords
+
+In some cases you might want to give temporary access to your prototype. For example, for a round of user research or to show it to a stakeholder.
+
+To support this, you can create additional passwords. You can revoke these later whilst still providing access for your team via the primary password.
+
+To set additional passwords, you need to first add an environment variable `PASSWORD_KEYS` that lists the keys of the additional passwords.
+For example, to add password keys `PASSWORD_01` and `PASSWORD_02` you need to add the following environment variable where the: 
+- `name` is `PASSWORD_KEYS`, and the `value` is `PASSWORD_01,PASSWORD_02`
+
+The password keys are not the passwords, they just identify them. They can take any unique value that’s a valid environment variable.
+
+To specify the passwords, add an environment variable for each one, like this:
+- `name` is `PASSWORD_01`, and the `value` is `password01`
+- `name` is `PASSWORD_02`, and the `value` is `password02`
+
+Please make sure your prototype kit is version **13.15.0** or later to allow this functionality to work.