diff --git a/.travis.yml b/.travis.yml
index 05a0c196..0b6422ca 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -9,16 +9,16 @@ env:
 
 before_install:
   - docker login -u $ATAT_DOCKER_REGISTRY_USERNAME -p $ATAT_DOCKER_REGISTRY_PASSWORD $ATAT_DOCKER_REGISTRY_URL
-  - docker build --tag "$TESTER_IMAGE_NAME" . -f docker/tester/Dockerfile
+  - docker build --tag "${TESTER_IMAGE_NAME}" . -f docker/tester/Dockerfile
 
 script:
-  - docker run "$TESTER_IMAGE_NAME"
+  - docker run "${TESTER_IMAGE_NAME}"
 
 before_deploy:
-  - docker build --tag "$PROD_IMAGE_NAME" . -f docker/prod/Dockerfile
+  - docker build --tag "${PROD_IMAGE_NAME}" . -f docker/prod/Dockerfile
   - remote_image_name="${ATAT_DOCKER_REGISTRY_URL}/${PROD_IMAGE_NAME}:${git_sha}"
   - git_sha="$(git rev-parse --short HEAD)"
-  - docker tag "$PROD_IMAGE_NAME" "${remote_image_name}"
+  - docker tag "${PROD_IMAGE_NAME}" "${remote_image_name}"
   - docker images
   - docker push "${remote_image_name}"