chore: add docker configuration

.env.example

@@ -0,0 +1,10 @@
+# Database configuration
+POSTGRES_USER=postgres
+POSTGRES_PASSWORD=postgres
+POSTGRES_DB=goldbank
+
+# Prisma connection string
+DATABASE_URL=postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@db:5432/${POSTGRES_DB}?schema=public
+
+# API Configuration
+PORT=3000