Add Travis config.

Author: gkellogg

.travis.yml

@@ -0,0 +1,23 @@
+language: ruby
+bundler_args: --without debug
+script: "bundle exec rspec spec"
+before_install:
+  - 'gem update --system --conservative || (gem i "rubygems-update:~>2.7" --no-document && update_rubygems)'
+  - 'gem update bundler --conservative'
+env:
+  - CI=true
+rvm:
+  - 2.2.2
+  - 2.3
+  - 2.4
+  - 2.5
+  - 2.6
+  - jruby
+  - rbx-3
+cache: bundler
+sudo: false
+matrix:
+  allow_failures:
+    - rvm: jruby
+    - rvm: rbx-3
+dist: trusty