Add day four Bingo player

main.go

@@ -5,6 +5,7 @@ import (
 	"os"
 	"strings"
 
+	"unsupervised.ca/aoc2021/four"
 	"unsupervised.ca/aoc2021/one"
 	"unsupervised.ca/aoc2021/three"
 	"unsupervised.ca/aoc2021/two"
@@ -31,6 +32,8 @@ func main() {
 		day = two.Init("two/input.txt")
 	case "three":
 		day = three.Init("three/input.txt")
+	case "four":
+		day = four.Init("four/input.txt")
 	default:
 		fmt.Printf("%q does not have a solution.\n", flagParts[1])
 		help()