Server confuses hostname, user_handle_domains and available_user_domains #33

Situation

Summarized as this server backend configuration (config.toml):

[server]
hostname = "bluesky.example.com"
user_handle_domains = [ "example.social" ]
available_user_domains = [ "example.social" ]

Users can reach the server's user interface through: https://bluesky.example.com/

What happens

When registering an account, the server registers a user handle as: username.bluesky.example.com

Note that bluesky.example.com is not an allowed value in user_handle_domains and available_user_domains.

What should happen

When registering an account, the server should register a user handle as: username.example.social