Block.swift

struct Block {
    
    init(timestamp: Date, data: String, previousBlockHash: Int) {
        
        self.timestamp = timestamp
        self.data = data
        self.previousBlockHash = previousBlockHash
        
      // For now lets just get some fields, concatenate them, and calculate a hash
        let basicHash = String(previousBlockHash) + data + String(timestamp.timeIntervalSince1970)
        hash = basicHash.hashValue
    }
    
    let timestamp: Date
    let data: String
    let previousBlockHash: Int
    let hash: Int
}