Basic concept of blockchain

Blockchain/main.swift

@@ -8,5 +8,25 @@
 
 import Foundation
 
-print("Hello, World!")
+let blockchain = Blockchain()
+var command: String?
 
+blockchain.createGenesisBlock(data: "")
+
+repeat {
+    print("Enter command:")
+    command = readLine()
+    
+    if command == "create" {
+        print("data for the new block:")
+        let data = readLine()
+        blockchain.createBlock(data: data ?? "")
+    }
+    
+    if command == "spam" {
+        for _ in 1...1000000 {
+            blockchain.createBlock(data: "\((blockchain.chain.last?.index ?? 0)+1)")
+        }
+    }
+    
+} while command != "exit"