add more examples and descriptions

README.md

@@ -6,15 +6,15 @@ Docker image with useful CI/CD tools optimized for use in GitLab CI pipelines.
 
 - bash
 - curl
-- Docker
-- Docker Buildx
-- Docker Compose
+- [Docker](https://docs.docker.com/engine/reference/commandline/cli/)
+- [Docker Buildx](https://docs.docker.com/build/architecture/#buildx)
+- [Docker Compose](https://docs.docker.com/get-started/08_using_compose/)
 - git
 - openssl
-- regctl
+- [regctl](https://github.com/regclient/regclient) (for advanced image handling)
 - rsync
-- sshpass
-- trivy
+- [sshpass](https://www.redhat.com/sysadmin/ssh-automation-sshpass) (for SSH servers with password authentication)
+- [trivy](https://aquasecurity.github.io/trivy/v0.45/)
 
 ## Dependencies
 
@@ -31,9 +31,23 @@ default:
 
 ## Usage examples
 
+### Build images with Docker Compose
+
+Specify `COMPOSE_FILE` if different from the default: `docker-compose.yml`. See [Docker Compose documentation](https://docs.docker.com/compose/compose-file/build/) for more details.
+
+```yaml
+build_app:
+  variables:
+    COMPOSE_FILE: docker-compose.build.yml
+  stage: build
+  script:
+    - docker-compose build app
+    - docker-compose push app
+```
+
 ### Run trivy
 
-Adjust the image-name and tag after copying the command to your `.gitlab-ci.yml`.
+Adjust the image-name and tag after copying the command to your `.gitlab-ci.yml`. See [trivy documentation](https://aquasecurity.github.io/trivy/v0.45/docs/target/container_image/) for more details.
 
 ```yaml
 container_scan: