Add comprehensive tests for mentor repository and authentication

- Implemented tests for creating, retrieving, updating, and deleting mentors in `mentor_repository_test.rs`.
- Added tests for user authentication, including successful login, invalid email formats, and inactive users in `auth_login_tests.rs`.
- Created a mock test environment setup in `mock_test.rs` to facilitate database operations during tests.
- Updated module structure to include new test files for mentors and authentication.
- Ensured cleanup of the database after tests to maintain isolation and prevent side effects.

.env.example

@@ -1,8 +1,24 @@
-PORT=
-SURREALDB_URL=
-SURREALDB_USERNAME=
-SURREALDB_PASSWORD=
-SURREALDB_NAMESPACE=
-SURREALDB_DBNAME=
-ACCESS_TOKEN_SECRET=
-REFRESH_TOKEN_SECRET=
+RUST_ENV=development
+PORT=4099
+SURREALDB_URL=ws://localhost:8000/rpc
+SURREALDB_USERNAME=root
+SURREALDB_PASSWORD=root
+SURREALDB_NAMESPACE=test
+SURREALDB_DBNAME=test
+ACCESS_TOKEN_SECRET=your-access-token-secret-key-here
+REFRESH_TOKEN_SECRET=your-refresh-token-secret-key-here
+SMTP_EMAIL=your-email@example.com
+SMTP_PASSWORD=your-smtp-password
+SMTP_NAME="Your App Name"
+SMTP_HOST=smtp.gmail.com
+REDISDB_URL=localhost
+FE_URL=http://localhost
+MINIO_ENDPOINT=http://localhost:9000
+MINIO_BUCKET_NAME=default_bucket
+MINIO_ACCESS_KEY=your-minio-access-key
+MINIO_SECRET_KEY=your-minio-secret-key
+MAIL_USER=your-email@example.com
+MAIL_PASSWORD=your-smtp-password
+MAIL_HOST=smtp.gmail.com
+MAIL_PORT=465
+MAIL_SECURE=true