ruby on rails - ActiveRecord undefined method OR -

this works without .or() breaks when add it:

<% @expired = report.where('expired < ?', date.new(2014,12,31)).or(report.where(expired: nil)).where(:major => 1).where.not(:tribe => 1).where(:permit_type => 'general') %> 

and gives me error:

undefined method `or' #<report::activerecord_relation:0x953e020> 

also, doing gives me syntax error:

report.where('expired < ?', date.new(2014,12,31) or (expired: nil)) 

how can make or work?

rails 4.2.1

try

report.where("expired null or expired < ?", date.new(2014,12,31)) 

and bigger query this

report.where("expired null or expired < ?", date.new(2014,12,31)).where(major: 1, permit_type: "general" ).where.not(tribe: 1)