code: function doesAutoScalingGroupExist (autoScaling, asgName) {
    return autoScaling
      .describeAutoScalingGroupsPromised({
        AutoScalingGroupNames: [ asgName ]
      })
      .then(function found (data) {
        return !_.isEmpty(data.AutoScalingGroups)
      })
  }
docs: Uses AutoScaling.describeAutoScalingGroups to check existence of the
  auto scaling group. If the list of AutoScalingGroups returned is empty
  doesAutoScalingGroupExist is resolved as False, if it's not empty it is
  resolved as True.
  
  @param autoScaling
  @param asgName
  
  @returns {Promise}