simplify ActiveAdmin::BatchActions::BatchActionPopover#action
Merge pull request #3139 from timoschilling/code_simplification

simplify ActiveAdmin::BatchActions::BatchActionPopover#action
support ransack short matchers
remove double if
Merge pull request #3144 from timoschilling/rm_doubled_if

remove double if
Merge pull request #3141 from timoschilling/support_short_predicates

support ransack short matchers