Add README and CI workflow for build and test

Author: tanettrimas

README.md

@@ -0,0 +1,50 @@
+# Feedback
+
+A feedback collection service for JavaZone, built with Kotlin and Ktor.
+
+## Prerequisites
+
+- JDK 25
+- Docker (for running PostgreSQL locally and tests)
+
+## Getting started
+
+Start the database:
+
+```bash
+docker compose up -d
+```
+
+Run the application:
+
+```bash
+./gradlew :core:run
+```
+
+The server starts on `http://localhost:8080`.
+
+## Configuration
+
+Configuration is done via environment variables. See `.env.example` for available options.
+
+## Testing
+
+Tests use Testcontainers and require a running Docker daemon.
+
+```bash
+./gradlew test
+```
+
+## Building
+
+Build a fat JAR for deployment:
+
+```bash
+./gradlew :core:buildFatJar
+```
+
+Build the Docker image:
+
+```bash
+docker build -t feedback .
+```