only allow guests to register for specific events; don't even show them the other trips

src/model/user.rs

@@ -17,7 +17,7 @@ pub struct User {
     pw: Option<String>,
     pub is_cox: bool,
     pub is_admin: bool,
-    is_guest: bool,
+    pub is_guest: bool,
     #[serde(default = "bool::default")]
     deleted: bool,
 }