feat(backend): migrate database from hardcoded SQLite to environment-based PostgreSQL configuration

[portableDD]

Description

app.module.ts hardcodes SQLite as the database with synchronize: true. SQLite files are wiped on every deployment on ephemeral hosting platforms (Render, Railway, Fly.io). ByteChain Academy cannot deploy to production until switched to environment-based PostgreSQL.

Background

Current config: type: 'sqlite', database: 'database.sqlite', synchronize: true

• SQLite file lost on every restart on cloud hosting
• synchronize: true in production risks dropping columns on deploy
• No connection pooling, no SSL support

Required additions to .env.example

DB_HOST=localhost
DB_PORT=5432
DB_USERNAME=postgres
DB_PASSWORD=your_password
DB_DATABASE=bytechain_academy
DB_SSL=false
NODE_ENV=development

Implementation Guide

Replace TypeOrmModule.forRoot with TypeOrmModule.forRootAsync using ConfigService. Read all DB settings from env vars. Set synchronize: true only when NODE_ENV !== 'production'. Enable SSL when DB_SSL === 'true' with rejectUnauthorized: false. Update e2e tests to use SQLite in-memory override so CI does not need a PostgreSQL instance.

Acceptance Criteria

• TypeOrmModule.forRootAsync with env-based PostgreSQL config
• synchronize: true only when NODE_ENV !== 'production'
• All DB vars in .env.example with comments
• Application connects to PostgreSQL when vars are set
• E2e tests still work with SQLite in-memory override
• npm run start:dev works with local PostgreSQL

Complexity: High - 200 points
Join: https://t.me/ByteChainAcademy | Contact: contact@nexacore.org

[TheBigWealth89]

@TheBigWealth89 has applied to work on this issue as part of the Stellar Wave Program's 4th wave.

I'll like to work on this project

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