def update_stack_list!
      if updater.nil? || !updater.alive?
        self.updater = Thread.new {
          loop do
            begin
              fetch_stacks
              sleep(stack_list_interval)
            rescue => e
              logger.error "Failure encountered on stack fetch: #{e.class} - #{e}"
            end
          end
        }
        true
      else
        false
      end
    end
def update_stack_list!
      if updater.nil? || !updater.alive?
        self.updater = Thread.new {
          loop do
            begin
              fetch_stacks
              sleep(stack_list_interval)
            rescue => e
              logger.error "Failure encountered on stack fetch: #{e.class} - #{e}"
            end
          end
        }
        true
      else
        false
      end
    end
Start async stack list update. Creates thread that loops every
 `self.stack_list_interval` seconds and refreshes stack list in cache

 @return [TrueClass, FalseClass]