Fix typo in Gemfile

[ci skip]
FIX: cache emojis for 1 year
Rename CsvExportLog to UserExport
Ruby 2.2 fixes
PERF: improve rendering speed of topic header

This also ensures we have a clean point to override rendering of topic list header
in case we decide to add/remove columns, you no longer need to override the
entire discovery template, only the header and item templates.
possible regression fix
FIX: log only 1 'show email' record
FIX: user card can't expand when the username is number
Merge pull request #3064 from fantasticfears/fix-user-card-number

FIX: user card can't expand when the username is number
Merge pull request #3061 from techAPJ/patch-1

Rename CsvExportLog to UserExport
Merge pull request #3059 from simi/patch-1

Fix typo in Gemfile
Added eu-central-1 S3 bucket.