Create a test matrix on Travis CI to help testing multiple options

.travis.yml

@@ -7,16 +7,18 @@ language: python
 
 python: 3.6
 
-env:
-  - TOX_ENV=py36
-
 before_install:
   - docker-compose -v
   - docker -v
 
-script:
-  - tox -e $TOX_ENV
-  - sh tests/test_docker.sh
+matrix:
+  include:
+    - name: Tox test
+      script: tox -e py36
+    - name: Basic Docker
+      script: sh tests/test_docker.sh
+    - name: Docker with Celery
+      script: sh tests/test_docker.sh use_celery=y
 
 install:
   - pip install tox

tests/test_docker.sh

@@ -11,7 +11,7 @@ mkdir -p .cache/docker
 cd .cache/docker
 
 # create the project using the default settings in cookiecutter.json
-cookiecutter ../../ --no-input --overwrite-if-exists use_docker=y
+cookiecutter ../../ --no-input --overwrite-if-exists use_docker=y $@
 cd my_awesome_project
 
 # run the project's type checks