appveyor.yml in active_model_serializers-0.10.6 vs appveyor.yml in active_model_serializers-0.10.7

@@ -3,22 +3,20 @@
 skip_tags: true
 
 environment:
   JRUBY_OPTS: "--dev -J-Xmx1024M --debug"
   matrix:
-    - ruby_version: "Ruby21"
-    - ruby_version: "Ruby21-x64"
+    - ruby_version: "Ruby23"
+    - ruby_version: "Ruby23-x64"
 
 cache:
   - vendor/bundle
 
 install:
   - SET PATH=C:\%ruby_version%\bin;%PATH%
-  - gem update --system
-  - gem uninstall bundler -a -x
-  - gem install bundler -v 1.13.7
   - bundle env
-  - bundle install --path=vendor/bundle --retry=3 --jobs=3
+  - bundle check || bundle install --path=vendor/bundle --retry=3 --jobs=3
+  - bundle clean --force
 
 before_test:
   - ruby -v
   - gem -v
   - bundle -v