Replace Travis CI with GitHub Actions

.github/workflows/ci.yml

@@ -0,0 +1,18 @@
+name: CI
+on:
+  - pull_request
+  - push
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Build rootfs tarball
+        run: |
+         sudo ./alpine-make-rootfs \
+              --branch v3.15 \
+              --packages 'ruby sqlite' \
+              --script-chroot \
+              example-$(date +%Y%m%d).tar.gz -- ./example/install.sh

.travis.yml

@@ -1,17 +0,0 @@
-sudo: required
-language: minimal
-script:
-  - sudo ./alpine-make-rootfs
-        --branch v3.9
-        --packages 'ruby ruby-bigdecimal sqlite'
-        --script-chroot
-        example-$(date +%Y%m%d).tar.gz -- ./example/install.sh
-#deploy:
-#  provider: releases
-#  api_key:
-#    secure: <Encrypted GitHub Personal Token>
-#  file: "*.tar.xz"
-#  file_glob: true
-#  skip_cleanup: true
-#  on:
-#    tags: true

README.adoc

@@ -5,7 +5,7 @@
 :version: 0.5.1
 
 ifdef::env-github[]
-image:https://travis-ci.org/{gh-name}.svg?branch=master["Build Status", link="https://travis-ci.org/{gh-name}"]
+image:https://github.com/{gh-name}/workflows/CI/badge.svg["Build Status", link="https://github.com/{gh-name}/actions"]
 endif::env-github[]
 
 This project provides a script for building customized https://alpinelinux.org/[Alpine Linux] rootfs (a base image if you like) for containers.
@@ -26,7 +26,7 @@ TIP: Do you want to just quickly chroot into Alpine Linux, e.g. on CI?
 == Usage
 
 Read documentation in link:{script-name}[{script-name}].
-See link:.travis.yml[.travis.yml] for Travis example.
+See link:.github/workflows/ci.yml[] for GitHub Actions example.
 
 You can copy link:{script-name}[{script-name}] into your repository or download it on demand, e.g.: