Add default TTL

Author: MGatner

app/Config/Cache.php

@@ -82,6 +82,21 @@ class Cache extends BaseConfig
 	 */
 	public $prefix = '';
 
+	/**
+	 * --------------------------------------------------------------------------
+	 * Default TTL
+	 * --------------------------------------------------------------------------
+	 *
+	 * The default number of seconds to save items when none is specified.
+	 *
+	 * WARNING: This is not used by framework handlers where 60 seconds is
+	 * hard-coded, but may be useful to projects and modules. This will replace
+	 * the hard-coded value in a future release.
+	 *
+	 * @var integer
+	 */
+	public $ttl = 60;
+
 	/**
 	 * --------------------------------------------------------------------------
 	 * File settings

user_guide_src/source/libraries/caching.rst

@@ -59,6 +59,12 @@ more complex, multi-server setups.
 If you have more than one application using the same cache storage, you can add a custom prefix
 string here that is prepended to all key names.
 
+**$ttl**
+
+The default number of seconds to save items when none is specified.
+WARNING: This is not used by framework handlers where 60 seconds is hard-coded, but may be useful
+to projects and modules. This will replace the hard-coded value in a future release.
+
 **$file**
 
 This is an array of settings specific to the  ``File`` handler to determine how it should save the cache files.