Use Travis CI for continuous integration

.travis.yml

@@ -0,0 +1,32 @@
+language: ruby
+
+sudo: false
+
+dist: trusty
+
+rvm:
+  - 2.3.4
+  - 2.4.1
+
+addons:
+  apt:
+    packages:
+      - libopencv-dev
+
+env:
+  global:
+    - PATH=/usr/lib/ccache:$PATH
+
+cache:
+  bundler: true
+  directories:
+    - $HOME/.ccache
+
+before_script:
+  - ruby ext/opencv/extconf.rb
+  - make
+  - make install
+
+script:
+  - cd test
+  - ruby runner.rb