Travis: add `--clean` in `bundle install` command.

diff --git a/.travis.yml b/.travis.yml
index fbd6d7401ac777c311516a884ac5e02e0d8aa413..841d179717d17bcc12f9f2d81e65fde4ba8231a0 100644 (file)
--- a/.travis.yml
+++ b/.travis.yml
@@ -8,7 +8,7 @@ node_js:
   - "6"
   - "8"
 install:
-  - bundle install --deployment --jobs=3 --retry=3
+  - bundle install --deployment --jobs=3 --retry=3 --clean
   - npm install
 script:
   - npm test