Add forceRefresh option to describe

This option lets you bypass cached data and always get fresh metadata.

src/Console/Command/OrmCacheShell.php

@@ -50,7 +50,7 @@ public function build($name = null) {
 		}
 		foreach ($tables as $table) {
 			$this->_io->verbose('Building metadata cache for ' . $table);
-			$schema->describe($table);
+			$schema->describe($table, ['forceRefresh' => true]);
 		}
 		$this->out('<success>Cache build complete</success>');
 	}

src/Database/Schema/Collection.php

@@ -86,14 +86,22 @@ public function listTables() {
  * Caching will be applied if `cacheMetadata` key is present in the Connection
  * configuration options. Defaults to _cake_model_ when true.
  *
+ * ### Options
+ *
+ * - `forceRefresh` - Set to true to force rebuilding the cached metadata.
+ *   Defaults to false.
+ *
  * @param string $name The name of the table to describe.
+ * @param array $options The options to use, see above.
  * @return \Cake\Database\Schema\Table Object with column metadata.
  * @throws \Cake\Database\Exception when table cannot be described.
  */
-	public function describe($name) {
+	public function describe($name, array $options) {
+		$options += ['forceRefresh' => false];
 		$cacheConfig = $this->cacheMetadata();
-		if ($cacheConfig) {
-			$cacheKey = $this->cacheKey($name);
+		$cacheKey = $this->cacheKey($name);
+
+		if (!empty($cacheConfig) && !$options['forceRefresh']) {
 			$cached = Cache::read($cacheKey, $cacheConfig);
 			if ($cached !== false) {
 				return $cached;