.travis.yml in posgra-0.1.8 vs .travis.yml in posgra-0.1.9

@@ -9,8 +9,11 @@
 script:
   - bundle install
   - bundle exec rake
 addons:
   postgresql: "9.4"
+  apt:
+    packages:
+      - libgmp-dev
 env:
   global:
     - POSGRA_TEST_USER=postgres