basic frontend (#3)

Co-authored-by: aovantsev <aovantsev@avito.ru>
Reviewed-on: #3

env.example

@@ -0,0 +1,12 @@
+# Database Configuration
+DATABASE_URL=postgres://postgres:password@localhost:5432/counter_db?sslmode=disable
+
+# JWT Configuration
+JWT_SECRET=your-super-secret-jwt-key-change-in-production
+
+# Server Configuration
+PORT=8080
+GIN_MODE=release
+
+# Frontend Configuration (for development)
+REACT_APP_API_URL=http://localhost:8080/api/v1