Document RBAC user creation with REST API

Page https://developer.couchbase.com/documentation/server/5.0/rest-api/rbac.html 

contains documentation for Role Based Admin Access (RBAC).

However, there is no reference to user creation endpoint (settings/rbac/users/local/<username>)

Document user creation and provide example like:

curl -X PUT http://Administrator:password@192.168.56.101:8091/settings/rbac/users/local/carlos -d 'roles=Admin&password=mi_password' 

Same for external domain.