chore: add Travis configuration.

.travis.yml

@@ -6,6 +6,9 @@ go:
 
 dist: xenial
 
+services:
+  - docker
+
 env:
   - GO111MODULE=on
 
@@ -22,6 +25,15 @@ before_install:
 install:
   - echo "TRAVIS_GO_VERSION=$TRAVIS_GO_VERSION"
   - go mod download
+  - echo "TRAVIS_GO_VERSION=$TRAVIS_GO_VERSION"
+  - go mod download
+
+before_deploy:
+  - >
+    if ! [ "$BEFORE_DEPLOY_RUN" ]; then
+      export BEFORE_DEPLOY_RUN=1;
+      echo "${DOCKER_PASSWORD}" | docker login -u "${DOCKER_USERNAME}" --password-stdin
+    fi
 
 deploy:
   - provider: script
@@ -30,3 +42,9 @@ deploy:
     on:
       tags: true
       condition: $TRAVIS_GO_VERSION =~ ^1\.x$
+  - provider: script
+    skip_cleanup: true
+    script: make publish-images
+    on:
+      tags: true
+      condition: $TRAVIS_GO_VERSION =~ ^1\.x$