CalDAV support (#15)

pkg/utils/sha256.go

@@ -0,0 +1,11 @@
+package utils
+
+import (
+	"crypto/sha256"
+	"fmt"
+)
+
+// Sha256 calculates a sha256 hash from a string
+func Sha256(cleartext string) string {
+	return fmt.Sprintf("%x", sha256.Sum256([]byte(cleartext)))[:45]
+}