Fixes leave on the server and reworked login flow.

gamenight-cli/src/domain/participants.rs

@@ -0,0 +1,12 @@
+use std::fmt::Display;
+
+use crate::domain::user::User;
+
+pub struct Participants<'a>(pub &'a Vec<User>);
+
+impl<'a> Display for Participants<'a> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        let string_list: Vec<String> = self.0.iter().map(|x| {format!("{}", x)}).collect();
+        write!(f, "{}", string_list.join(", "))
+    }
+}