Proper Travis CI config & test against mysql also

.travis.yml

@@ -1,7 +1,28 @@
-before_install: gem install bundler
-before_script:
-  - "bundle exec rake test_app"
-script: "DISPLAY=:99.0 bundle exec rspec spec"
+sudo: required
+dist: trusty
+
+language: ruby
+
+env:
+  - DB=postgres
+  - DB=mysql
+
+gemfile:
+  - gemfiles/spree_3_1.gemfile
+  - gemfiles/spree_3_2.gemfile
+  - gemfiles/spree_master.gemfile
+
+script:
+  - bundle exec rake test_app
+  - bundle exec rake spec
+
 rvm:
-  - 2.2.4
-  - 2.3.0
+  - 2.3.1
+  - 2.2.5
+
+addons:
+  apt:
+    packages:
+    - mysql-server-5.6
+    - mysql-client-core-5.6
+    - mysql-client-5.6

spree_active_shipping.gemspec

@@ -29,5 +29,6 @@ Gem::Specification.new do |s|
   s.add_development_dependency 'rspec-rails'
   s.add_development_dependency 'rspec-activemodel-mocks'
   s.add_development_dependency 'pg'
+  s.add_development_dependency 'mysql2'
   s.add_development_dependency 'appraisal'
 end