fix gemspec
Merge pull request #1 from norifumi/work

fix gemspec
Added a scope
Merge pull request #2 from johnny-miyake/order_by_id_desc

Added a scope
Merge pull request #3 from framgia/develop

Develop
Merge pull request #4 from framgia/master

from master
fixed dependent rails version in gemspec
Merge pull request #5 from johnny-miyake/fix_gemspec

fixed dependent rails version in gemspec