title: Type does not conform to protocol 'Decodable'/'Encodable'
body: <p>I have the following data class which I have tried adding an array of AdditionalCharge to but get the error specified in the title.</p>
  
  <p>The AdditionalCharge class and the FundingRequest class containing the additional charge is below.</p>
  
  <p>I'm not sure what I've done wrong. </p>
  
  <pre><code>class AdditionalCharge{
      var ItemDescription = ""
      var ItemValue:String = ""
  }
  
  class FundingRequest: Codable {
  let dispatcherName, loadReference, origin, destination: String
  let userID: String, applicationID: String
  let pickedUp, droppedOff: String
  let driverFirstName, driverLastName: String
  let grossTruckPay,fundingMethod, comments: String
  let advancesTaken: Bool
  let rateConfirmation, billOfLading, lumperReceipt: [String]
  let salesTicket: [String]
  let debtorID: String
  let additionalCharges = [AdditionalCharge]()
  enum CodingKeys: String, CodingKey {
      case dispatcherName = "DispatcherName"
      case loadReference = "LoadReference"
      case origin = "Origin"
      case destination = "Destination"
      case userID = "UserID"
      case applicationID = "ApplicationID"
      case pickedUp = "PickedUp"
      case droppedOff = "DroppedOff"
      case driverFirstName = "DriverFirstName"
      case driverLastName = "DriverLastName"
      case grossTruckPay = "GrossTruckPay"
      case advancesTaken = "AdvancesTaken"
      case fundingMethod = "FundingMethod"
      case comments = "Comments"
      case additionalCharges = "AdditionalCharges"
      case rateConfirmation = "RateConfirmation"
      case billOfLading = "BillOfLading"
      case lumperReceipt = "LumperReceipt"
      case salesTicket = "SalesTicket"
      case debtorID = "DebtorID"
  }
  
  init(dispatcherName: String, loadReference: String, origin: String, destination: String, userID: String,applicationID: String, pickedUp: String, droppedOff: String, driverFirstName: String, driverLastName: String, grossTruckPay: String, advancesTaken: Bool, fundingMethod: String, comments: String, additionalCharges: [AdditionalCharge], rateConfirmation: [String], billOfLading: [String], lumperReceipt: [String], salesTicket: [String], debtorID:String) {
      self.dispatcherName = dispatcherName
      self.loadReference = loadReference
      self.origin = origin
      self.destination = destination
      self.userID = userID
      self.pickedUp = pickedUp
      self.droppedOff = droppedOff
      self.driverFirstName = driverFirstName
      self.driverLastName = driverLastName
      self.grossTruckPay = grossTruckPay
      self.advancesTaken = advancesTaken
      self.fundingMethod = fundingMethod
      self.comments = comments
      self.additionalCharges = additionalCharges
      self.rateConfirmation = rateConfirmation
      self.billOfLading = billOfLading
      self.lumperReceipt = lumperReceipt
      self.salesTicket = salesTicket
      self.debtorID = debtorID
      self.applicationID = applicationID
  }
  </code></pre>