feat: allow more safe characters in the username

README.md

@@ -45,8 +45,8 @@ people joining in with the respective privileges. Further, `bob@work` can join o
 `h@cafe`, whose comment is tagged as `:admin` will be able to join the chat with admin privileges.
 
 > [!NOTE]
-Usernames may only contain ASCII alphanumeric characters and the `@`
-symbol. All other characters will be stripped.
+Usernames may only contain ASCII alphanumeric characters and the symbols `@-_.`.
+All other characters will be stripped.
 
 ### Getting started
 

src/authfile.rs

@@ -10,7 +10,7 @@ use russh::keys::ssh_key::public::KeyData;
 pub fn sanitize_name(s: &str) -> String {
     let mut sanitized = String::with_capacity(s.len());
     for c in s.chars() {
-        let ok = c.is_ascii_alphanumeric() || c == '@';
+        let ok = c.is_ascii_alphanumeric() || "@_-.".contains(c);
         if !ok {
             continue;
         }