.travis.yml in terraforming-0.10.0 vs .travis.yml in terraforming-0.11.0

- old
+ new
@@ -2,9 +2,15 @@
 rvm:
 - 2.3.1
 - 2.2.5
 - 2.1.10
 env:
-- secure: n0mxwnyjuXI4mJO4mp++2TnsPJ+XgCF/J1U2L5piE5j3xMhSU+5V0JrA1uFlS0Pemb44M7BjgmF9S4G35BwyAQpctpCYhqy9tFa6+Y6nxEv5hCv2cZz7BSAZM6eb+zq20409hxTHRaQOr1DBeE4R5S2PrmOXRqvYfTRv3LNSLFk=
+  global:
+    - secure: n0mxwnyjuXI4mJO4mp++2TnsPJ+XgCF/J1U2L5piE5j3xMhSU+5V0JrA1uFlS0Pemb44M7BjgmF9S4G35BwyAQpctpCYhqy9tFa6+Y6nxEv5hCv2cZz7BSAZM6eb+zq20409hxTHRaQOr1DBeE4R5S2PrmOXRqvYfTRv3LNSLFk=
+  matrix:
+    - OJ=0
+    - OJ=1
+before_script:
+  - if [[ $OJ -eq 1 ]]; then gem install oj; fi
 notifications:
   slack:
     secure: iTI8zpxXQJqf5e9ix4buLRsGlf9lJRZqA9Fawdqm41msBrC0Zsp31XzBS7ZPiTcdHhImtOC4lccTCW2C8kR6waaG5VOF0U2BwyKaNFKsXMaVk6yrNhYkvJ9YVicuU9hL+JKLyBrSDYQ7+vXcHqaz4H4dYpPThrv6sfq4jBOp+eM=