Replace faker gem with ffaker

ffaker is a drop-in replacement for faker that's up to 20x faster at
generating fake data.
Merge pull request #52 from patricklewis/faker-to-ffaker

Replace faker gem with ffaker
fixed #53 - mentioned the better_errors gem
mentioned bullet
mentioned globalize3
Added some missing "do" keywords.
Merge pull request #54 from vakuum/pr-1

Added some missing "do" keywords.
Merge pull request #4 from bbatsov/master

Update