Add ruby-head to Travis. (#8)

* Add ruby-head to Travis.
* Remove remove-wire-protocol-to-plugin branch.
  That causes error for "build install".
* Set Ruby 1.9.3 and JRuby as allow_failures because of the test failure.

.travis.yml

@@ -1,11 +1,20 @@
 rvm:
-  - 2.4
+  - ruby-head
+  - 2.4.0
+  - 2.3.3
   - 2.2
   - 2.1
   - 2.0
   - 1.9.3
   - jruby-1.7.12
 
+matrix:
+  allow_failures:
+    - rvm: ruby-head
+    - rvm: 1.9.3
+    - rvm: jruby-1.7.12
+  fast_finish: true
+
 # whitelist
 branches:
   only:

Gemfile

@@ -5,9 +5,9 @@ unless ENV['CUCUMBER_USE_RELEASED_GEMS']
   # cucumber gem
   cucumber_path = File.expand_path("../../cucumber-ruby", __FILE__)
   if File.exist?(cucumber_path) && !ENV['CUCUMBER_USE_GIT']
-    gem "cucumber", path: cucumber_path, branch: "remove-wire-protocol-to-plugin"
+    gem "cucumber", path: cucumber_path
   else
-    gem "cucumber", :git => "git://github.com/cucumber/cucumber-ruby.git", branch: "remove-wire-protocol-to-plugin"
+    gem "cucumber", :git => "git://github.com/cucumber/cucumber-ruby.git"
   end
 
   # cucumber-core gem