feat: Remove the session on the server

frontend/src/components/app.tsx

@@ -275,7 +275,16 @@ export default class Application extends React.Component<IProps> {
     }
 
     logout = () => {
-        // TODO: Tell the server that we're logging ourselves out
+        // NOTE: No promise, since we don't care about the result
+        fetch(`${BACKEND_URL}/api/user/logout`, {
+            headers: new Headers({
+                "Content-Type": "application/json",
+                "Token": this.props.user.sessionToken,
+            }),
+            method: "GET",
+        });
+
+        // Remove the session locally
         removeSessionToken(window);
         this.props.setAuthenticated(false);
     }