Merge remote-tracking branch 'origin/master' into arthur/fix-enumerator-returns

Author: carlosmn

.travis.yml

@@ -3,13 +3,13 @@ cache: bundler
 
 os:
   - linux
+  - osx
 
 rvm:
-  - 2.0.0
-  - 2.1.8
   - 2.2.5
   - 2.3.3
   - 2.4.0
+  - 2.5.0
   - ruby-head
   - rbx-2
 
@@ -26,23 +26,16 @@ sudo: required
 matrix:
   fast_finish: true
   allow_failures:
+    - rvm: 2.5.0
     - rvm: rbx-2
     - rvm: ruby-head
-  include:
-    - os: osx
-      rvm: 2.0.0
-    - os: osx
-      rvm: 2.1.5
-    - os: osx
-      rvm: 2.2.2
-    - os: osx
-      rvm: rbx-2
 
 git:
   submodules: false
 
 before_install:
   - git submodule update --init
+  - gem update --system
   - if [ "$TRAVIS_OS_NAME" = "osx" ]; then ./vendor/libgit2/script/install-deps-osx.sh; fi
 
 script: script/travisbuild