Add FileCache driver

app/Core/Cache/CacheInterface.php

@@ -1,45 +0,0 @@
-<?php
-
-namespace Kanboard\Core\Cache;
-
-/**
- * Cache Interface
- *
- * @package  cache
- * @author   Frederic Guillot
- */
-interface CacheInterface
-{
-    /**
-     * Save a new value in the cache
-     *
-     * @access public
-     * @param  string  $key
-     * @param  string  $value
-     */
-    public function set($key, $value);
-
-    /**
-     * Fetch value from cache
-     *
-     * @access public
-     * @param  string  $key
-     * @return mixed            Null when not found, cached value otherwise
-     */
-    public function get($key);
-
-    /**
-     * Clear all cache
-     *
-     * @access public
-     */
-    public function flush();
-
-    /**
-     * Remove cached value
-     *
-     * @access public
-     * @param  string  $key
-     */
-    public function remove($key);
-}