# Add device_id Field

## Context
User requested to add a `device_id` field (string) to the Kafka payload and database table.

## Changes
1.  **Documentation**:
    - Updated `docs/readme.md` to include `device_id` in the table structure.
    - Updated `docs/kafka_format.md` to include `device_id` in the JSON schema and examples.

2.  **Database**:
    - Updated `bls-rcu-action-backend/scripts/init_db.sql` to add `device_id` column and a corresponding index.

3.  **Backend Code**:
    - `src/schema/kafkaPayload.js`: Added `device_id` to the Zod validation schema (string, required).
    - `src/db/databaseManager.js`: Added `device_id` to the list of columns for insertion.
    - `src/processor/index.js`: Updated logic to extract `device_id` from the payload and pass it to the row object.
    - `tests/processor.test.js`: Updated test cases to include `device_id` in the mock payload.

## Verification
- Unit tests updated and should pass.
- Schema changes aligned across documentation and code.
