add test suite. See #197

This test suite is implemented using [bats](https://github.com/sstephenson/bats).

Not all features are tested. For instance ssl features and custom nginx config are missing. Probably others.

This test suite won't work with TravisCI. Too many evenings were wasted trying to overcome [issues](http://stackoverflow.com/questions/32846800/travis-fails-to-stop-docker-containers) that arises only on the TravisCI platform. However it runs on [CircleCI](https://circleci.com) which is also free for opensource projects.

circle.yml

@@ -0,0 +1,21 @@
+machine:
+  pre:
+    # install docker 1.7.1
+    - sudo curl -L -o /usr/bin/docker 'https://s3-external-1.amazonaws.com/circle-downloads/docker-1.7.1-circleci'; sudo chmod 0755 /usr/bin/docker; true
+  services:
+    - docker
+
+dependencies:
+  override:
+    - sudo add-apt-repository ppa:duggan/bats --yes
+    - sudo apt-get update -qq
+    - sudo apt-get install -qq bats
+    - docker pull jwilder/docker-gen
+    - docker pull nginx
+    - docker pull python:3
+    - docker pull rancher/socat-docker
+
+test:
+  override:
+    - docker build -t jwilder/nginx-proxy:bats .
+    - bats test