Make drawings persist (save) to the backend

[mschmulen]

Currently Drawings are not saved to the backed so all the beautiful pictures and drawing that the child does is lost in the app interaction session.

AC:

• Drawings are saved after the kid make a modification to a drawing
• Kids can open up legacy drawings and improve them
• Adults and others can view readonly the drawing the kid has made.

[mschmulen]

dev notes:

• add "layer" to drawings.
• add "color" to drawing ( make use of codable enums, https://blog.untitledkingdom.com/codable-enums-in-swift-3ab3dacf30ce)
• swiftUI Color notes: https://troz.net/post/2020/swiftui-color/

    case name(String)
    case email(String)
}```

extension LoginType: Codable {

enum Key: CodingKey {
    case rawValue
    case associatedValue
}

enum CodingError: Error {
    case unknownValue
}

init(from decoder: Decoder) throws {
    let container = try decoder.container(keyedBy: Key.self)
    let rawValue = try container.decode(Int.self, forKey: .rawValue)
    switch rawValue {
    case 0:
        let userName = try container.decode(String.self, forKey: .associatedValue)
        self = .name(userName)
    case 1:
        let email = try container.decode(String.self, forKey: .associatedValue)
        self = .email(email)
    default:
        throw CodingError.unknownValue
    }
}

func encode(to encoder: Encoder) throws {
    var container = encoder.container(keyedBy: Key.self)
    switch self {
    case .name(let userName):
        try container.encode(0, forKey: .rawValue)
        try container.encode(userName, forKey: .associatedValue)
    case .email(let email):
        try container.encode(1, forKey: .rawValue)
        try container.encode(email, forKey: .associatedValue)
    }
}

}

https://blog.untitledkingdom.com/codable-enums-in-swift-3ab3dacf30ce
https://github.com/gregiOS/Playgrounds/

[mschmulen]

Done.