Generalise MySQLDate to lib

lib/MySQLDate.js

@@ -0,0 +1,15 @@
+'use strict';
+
+// Class for easy insertion of test dates into the database
+class MySQLDate extends Date {
+	toString() {
+		return this.toISOString().slice(0, 19).replace('T', ' ');
+	}
+
+	alterDays(amount) {
+		this.setDate(this.getDate() + amount);
+		return this;
+	}
+}
+
+module.exports = MySQLDate;