Add some configuration options for instance admins

plume-models/src/admin.rs

@@ -0,0 +1,19 @@
+use rocket::{Outcome, http::Status, request::{self, FromRequest, Request}};
+
+use users::User;
+
+/// Wrapper around User to use as a request guard on pages reserved to admins.
+pub struct Admin(pub User);
+
+impl<'a, 'r> FromRequest<'a, 'r> for Admin {
+    type Error = ();
+
+    fn from_request(request: &'a Request<'r>) -> request::Outcome<Admin, ()> {
+        let user = request.guard::<User>()?;
+        if user.is_admin {
+            Outcome::Success(Admin(user))
+        } else {
+            Outcome::Failure((Status::Unauthorized, ()))
+        }
+    }
+}