.travis.yml in rack-app-2.3.0 vs .travis.yml in rack-app-2.3.1

- old
+ new

@@ -1,8 +1,12 @@
 language: ruby
 script: rspec spec
 
+install:
+  - gem update bundler
+  - bundle install
+
 rvm:
   - 1.8
   - 1.9
   - 2.0
   - 2.1
@@ -10,9 +14,21 @@
   - jruby-19mode
   - ree
 
   - ruby-head
   - jruby-head
+
+matrix:
+  include:
+
+    - rvm: ruby-head
+      before_install:
+        - 'gem update --system 2.4.8'
+
+
+  allow_failures:
+    - rvm: ruby-head
+    - rvm: jruby-head
 
 env:
   global:
     - VERBOSE=true
     - TIMEOUT=1