Add Google Analytics for prod
Add Google Analytics for prod

Test Plan:
Tested by changing 'prod' to 'dev', refreshing page, seeing update on
GA.

Reviewers: spicyj, xymostech

Differential Revision: http://phabricator.benalpert.com/D147

jonafato/vim-awesome,vim-awesome/vim-awesome,starcraftman/vim-awesome,jonafato/vim-awesome,divad12/vim-awesome,vim-awesome/vim-awesome,shaialon/vim-awesome,starcraftman/vim-awesome,vim-awesome/vim-awesome,shaialon/vim-awesome,divad12/vim-awesome,starcraftman/vim-awesome,starcraftman/vim-awesome,vim-awesome/vim-awesome,jonafato/vim-awesome,vim-awesome/vim-awesome,shaialon/vim-awesome,divad12/vim-awesome,jonafato/vim-awesome,shaialon/vim-awesome,divad12/vim-awesome