Re-add travis files

.travis.yml

@@ -0,0 +1,30 @@
+language: node_js
+git:
+  depth: false
+node_js:
+  - 16
+
+services:
+  - docker
+
+cache: yarn
+
+if: (type = pull_request) OR (tag IS present)
+
+jobs:
+  include:
+    - stage: Install dependencies
+      if: type = pull_request
+      script: yarn --frozen-lockfile
+    - stage: Check formatting
+      if: type = pull_request
+      script: yarn format:check
+    - stage: Execute tests
+      if: type = pull_request
+      script: yarn test
+    - stage: Build application
+      if: type = pull_request
+      script: yarn build:all
+    - stage: Build and publish docker image
+      if: tag IS present
+      script: ./publish-docker-image.sh

publish-docker-image.sh

@@ -0,0 +1,5 @@
+set -xe
+echo "$DOCKER_HUB_ACCESS_TOKEN" | docker login -u "$DOCKER_HUB_USERNAME" --password-stdin
+
+docker build -t ghostfolio/ghostfolio:$TRAVIS_TAG -t ghostfolio/ghostfolio:latest .
+docker push ghostfolio/ghostfolio --all-tags