Added arn to the main repository

arn/Spoiler.go

@@ -0,0 +1,11 @@
+package arn
+
+// Spoiler represents a text that can spoil a future event.
+type Spoiler struct {
+	Text string `json:"text" editable:"true" type:"textarea"`
+}
+
+// String returns the containing text.
+func (spoiler *Spoiler) String() string {
+	return spoiler.Text
+}