Travis: enable Composer cache

See:
- https://docs.travis-ci.com/user/caching/
- https://blog.wyrihaximus.net/2015/07/composer-cache-on-travis/

Signed-off-by: VirtualTam <virtualtam@flibidi.net>

1 files changed, 4 insertions, 1 deletions

diff --git a/.travis.yml b/.travis.yml
index 7408b2e2..9ffb3d00 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,5 +1,8 @@
 sudo: false
 language: php
+cache:
+  directories:
+    - $HOME/.composer/cache
 php:
   - 7.0
   - 5.6
@@ -8,7 +11,7 @@ php:
   - 5.3
 install:
   - composer self-update
-  - composer install
+  - composer install --prefer-dist
 script:
   - make clean
   - make check_permissions