<s>[INST] I used a PostgreSQL database for an application that allows restaurant owners to manage their menu items. I want to know more about how to use indexes to improve performance and query optimization.

To answer your question, here is the table for menu items:

```sql
CREATE TABLE menu_items (
    id SERIAL,
    name VARCHAR(50),
    description TEXT,
    price DECIMAL(5,2),
    category VARCHAR(20),
    created_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP,
    updated_at TIMESTAMP DEFAULT CURRENT_TIMESTAMP
);
```

I've noticed that my application has slowed down, and queries are taking longer than expected. I've done some analysis and found that the `category` column is used extensively in `WHERE` and `JOIN` clauses. Could you provide an example of how to create an index on the `category` column and explain the benefits of indexing?[/INST]