Authenticating to docker

Author: diemol

.travis.yml

@@ -14,10 +14,12 @@ jobs:
     - stage: Build and integration tests
       env: step=build_and_test
       script:
+      - docker login -u="$DOCKER_USERNAME" -p="$DOCKER_PASSWORD"
       - docker info
       - VERSION="$TRAVIS_BRANCH" make ci
     - env: step=build_and_test_random_user
       script:
+      - docker login -u="$DOCKER_USERNAME" -p="$DOCKER_PASSWORD"
       - docker info
       - USE_RANDOM_USER_ID=true VERSION="$TRAVIS_BRANCH" make ci
     - stage: Release