✨ Update Redis configuration and Docker setup; improve README and code structure for clarity

docker-compose.dev.yml

@@ -54,7 +54,7 @@ services:
       - redis
     environment:
       - NODE_ENV=development
-      - DATABASE_URL=sqlite://data/gitea-mirror.db
+      - DATABASE_URL=file:data/gitea-mirror.db
       - HOST=0.0.0.0
       - PORT=4321
       - JWT_SECRET=dev-secret-key
@@ -75,6 +75,7 @@ services:
       - GITEA_ORGANIZATION=${GITEA_ORGANIZATION:-github-mirrors}
       - GITEA_ORG_VISIBILITY=${GITEA_ORG_VISIBILITY:-public}
       - DELAY=${DELAY:-3600}
+      - REDIS_URL=redis://redis:6379
     healthcheck:
       test: ["CMD", "wget", "--no-verbose", "--tries=1", "--spider", "http://localhost:4321/"]
       interval: 30s