Specifies whether the records should be unique or not. For example:
User.select(:name)# => Might return two records with the same nameUser.select(:name).uniq# => Returns 1 record per unique nameUser.select(:name).uniq.uniq(false)# => You can also remove the uniqueness
# File activerecord/lib/active_record/relation/query_methods.rb, line 201
def uniq(value = true)
relation = clone
relation.uniq_value = value
relation
end