add readme for each package

hash.go

@@ -9,19 +9,11 @@ import (
 // SHA256 creates a hex-encoded SHA256 checksum for a string input.
 func SHA256(value string) string {
 	sum := sha256.Sum256([]byte(value))
-	hash := []byte{}
-	for _, b := range sum {
-		hash = append(hash, b)
-	}
-	return hex.EncodeToString(hash)
+	return hex.EncodeToString(sum[0:])
 }
 
 // SHA512 creates a hex-encoded SHA512 checksum for a string input.
 func SHA512(value string) string {
 	sum := sha512.Sum512([]byte(value))
-	hash := []byte{}
-	for _, b := range sum {
-		hash = append(hash, b)
-	}
-	return hex.EncodeToString(hash)
+	return hex.EncodeToString(sum[0:])
 }