Backend integration

**Description:**
Currently, the blind coding website does not store user submissions or problem data. To improve functionality, we need to integrate a database to manage programming problems, user progress, and submissions efficiently.

### **Requirements:**
- Store multiple programming problems with corresponding reference images and expected outputs.
- Save user submissions, progress, and performance data for analysis.
- Implement a backend service to fetch and update problems dynamically.
- Ensure database security and optimize queries for efficient performance.

### **Expected Outcome:**
Users can attempt multiple coding challenges, track their progress, and retrieve past submissions while ensuring seamless problem management.