def find_alias(associations = [])
      rel = _scope.joins _arel(associations)
      builder = JoinDependency::Builder.new(rel)
      builder.find_alias(associations)
    end
def find_alias(associations = [])
      rel = _scope.joins _arel(associations)
      builder = JoinDependency::Builder.new(rel)
      builder.find_alias(associations)
    end
When referencing a joined table, the tables that
 attributes reference can change (due to aliasing).
 This method allows BabySqueel::Nodes::Attribute
 instances to find what their alias will be.