Initial exercise setup.

Additions

* Instructions for manually starting the database.
* Each phase now has a success criteria with how to verify.
* Troubleshooting section for working with the Docker DB container.
* All phases of the exercise are described in README.md (with as little advanced hints as possible).
* DFD to illustrate phase 1
* Debugging starts the database container and applies schema migrations (no setup required).
* Launch settings for VS Code, VS 2022 and Rider (IntelliJ IDEA).
* Swagger UI is available at <http://localhost:8080/swagger/index.html> for testing.

docker-compose.yaml

@@ -0,0 +1,36 @@
+services:
+  service:
+    build:
+      context: .
+      dockerfile: Dockerfile
+    depends_on:
+      - db
+    networks:
+      - default
+    ports:
+      - "8080:8080"
+    environment:
+      ASPNETCORE_ENVIRONMENT: Docker
+
+  db:
+    image: postgres:alpine
+    restart: unless-stopped
+    networks:
+      - default
+    ports:
+      - "5432:5432" # Also for local development
+    environment:
+      POSTGRES_USER: user
+      POSTGRES_PASSWORD: password
+      POSTGRES_DB: mydatabase
+    volumes:
+      - db_data:/var/lib/postgresql/data
+      - ./dbschemas:/docker-entrypoint-initdb.d
+
+networks:
+  default:
+    driver: bridge
+
+volumes:
+  db_data:
+    driver: local