Merge pull request #165 from rspec/ruby_build_matrix_updates

Ruby build matrix updates

Author: JonRowe

travis/.travis.yml

@@ -19,6 +19,7 @@ rvm:
   - 2.1
   - 2.2.5
   - 2.3.1
+  - 2.4.0-preview1
   - ruby-head
   - ree
   - rbx
@@ -32,11 +33,14 @@ matrix:
       env: JRUBY_OPTS='--server -Xcompile.invokedynamic=false'
     - rvm: jruby
       env: JRUBY_OPTS='--server -Xcompile.invokedynamic=false'
+    - rvm: jruby-9.1.2.0
+      env: JRUBY_OPTS='--server -Xcompile.invokedynamic=false'
   allow_failures:
     - rvm: jruby-head
       env: JRUBY_OPTS='--server -Xcompile.invokedynamic=false'
     - rvm: ruby-head
     - rvm: rbx
+    - rvm: 2.4.0-preview1
   fast_finish: true
 branches:
   only: