Add the ability to change the keys (#348)

* feat: add the ability to change the session key store in redis

* feat: change everywhere the constants are used

* refactor: add formatting with cargo fmt

---------

Co-authored-by: Dany Gagnon <danygagnon@Danys-MacBook-Pro.local>

actix-identity/tests/integration/integration.rs

@@ -28,6 +28,33 @@ async fn login_works() {
     assert!(response.status().is_success());
 }
 
+#[actix_web::test]
+async fn custom_keys_work_as_expected() {
+    let custom_id_key = "custom.user_id";
+    let custom_last_visited_key = "custom.last_visited_at";
+    let custom_logged_in_key = "custom.logged_in_at";
+
+    let app = TestApp::spawn_with_config(
+        IdentityMiddleware::builder()
+            .id_key(custom_id_key)
+            .last_visit_unix_timestamp_key(custom_last_visited_key)
+            .login_unix_timestamp_key(custom_logged_in_key),
+    );
+    let user_id = user_id();
+
+    let body = app.post_login(user_id.clone()).await;
+    assert_eq!(body.user_id, Some(user_id.clone()));
+
+    let response = app.get_identity_required().await;
+    assert!(response.status().is_success());
+
+    let response = app.post_logout().await;
+    assert!(response.status().is_success());
+
+    let response = app.get_identity_required().await;
+    assert_eq!(response.status(), StatusCode::UNAUTHORIZED);
+}
+
 #[actix_web::test]
 async fn logging_in_again_replaces_the_current_identity() {
     let app = TestApp::spawn();