def add(member_address, options={})
      params = {:address => member_address}
      Mailgun.submit :post, list_member_url, params.merge(options)
    end
def add(member_address, options={})
      params = {:address => member_address}
      Mailgun.submit :post, list_member_url, params.merge(options)
    end
Adds a mailing list member with a given address
 NOTE Use create instead of add?