append_constraints

# File activerecord/lib/active_record/associations/join_dependency/join_association.rb, line 69
          def append_constraints(join, constraints)
            if join.is_a?(Arel::Nodes::StringJoin)
              join_string = table.create_and(constraints.unshift(join.left))
              join.left = Arel.sql(base_klass.connection.visitor.compile(join_string))
            else
              join.right.expr.children.concat(constraints)
            end
          end