Updating readme

README.md

@@ -1,2 +1,34 @@
 # alpine-builder
 Docker image with alpine linux to build apk's
+
+Created user `builder` with password `123` because `abuild -r` cannot be executed with root account. 
+
+
+### Usage:
+Here is illustration how to integrate this image with your CI/CD software,
+in this case i use GitLab CE + Sonatype Nexus as artifacts storage. Only one
+tricky thing is to create variable in GitLab CI with plain http auth to your
+Nexus server named `APK_REPO_CRED`.
+
+_.gitlab-ci.yml_
+```yaml
+image: jar3b/alpine-builder:3.6
+stages:
+  - release
+
+release:
+  stage: release
+  variables:
+    RV: "1.0.1-r1"
+    REPO: "https://nexus.example.org/repository/apk/myrepo"
+  script:
+    - su -c "abuild checksum" builder
+    - su -c "abuild -r" builder
+    - cd /home/builder/packages/${CI_PROJECT_NAMESPACE}/x86_64
+    - curl -v -u ${APK_REPO_CRED} --upload-file myrepo-$RV.apk $REPO/myrepo-$RV.apk
+    - curl -v -u ${APK_REPO_CRED} --upload-file myrepo-lib-$RV.apk $REPO/myrepo-lib-$RV.apk
+```
+
+### Available versions:
+- 3.5
+- 3.6 (latest)