Fix #2108 - Fix gif uploads (#2171)

* Fix #2108 - Fix gif uploads
Add specs for media attachment gifv conversion

* Add ffmpeg to travis

* Make travis install ffmpeg, not libav

* Switch travis to trusty

.travis.yml

@@ -1,5 +1,7 @@
 language: ruby
 cache: bundler
+dist: trusty
+sudo: required
 
 notifications:
   email: false
@@ -24,8 +26,9 @@ bundler_args: --without development production --retry=3 --jobs=3
 
 before_install:
   - sudo add-apt-repository -y ppa:ubuntu-toolchain-r/test
+  - sudo add-apt-repository -y ppa:mc3man/trusty-media
   - sudo apt-get -qq update
-  - sudo apt-get -qq install g++-4.8
+  - sudo apt-get -qq install g++-4.8 ffmpeg
 install:
   - nvm install
   - npm install -g yarn