WEB: Don't make the cache database depend on the hostname

This avoids having two caches when accessing the website with or without
a www and this is also more robust.
Make use of the DEV_SERVER constant and allow to enable it by setting an
environment variable.

Author: lephilousophe

include/Models/BasicModel.php

@@ -17,7 +17,7 @@ public function __construct()
         if (is_null(self::$cache)) {
             try {
                 $driver = extension_loaded('redis') ? 'redis' : 'predis';
-                $database = $_SERVER['HTTP_HOST'] === 'www.scummvm.org' ? 8 : 7;
+                $database = DEV_SERVER ? 7 : 8;
                 $config = extension_loaded('redis')
                     ? new RedisConfig(['database' => $database])
                     : new PredisConfig(['database' => $database]);

public_html/index.php

@@ -5,14 +5,22 @@
  * Development only
  * Don't re-route static file requests to index.php
  * And change directory context to public_html
+ *
+ * When DEV_SERVER is true a different Redis database is chosen
+ * It's true when running using PHP built-in server or
+ * if the DEV_SERVER environment variable is set to 1
  */
 if (isset($_SERVER['SERVER_SOFTWARE']) &&
-\preg_match("/PHP [\d\.]+ Development Server/",$_SERVER['SERVER_SOFTWARE'])) {
-  chdir('public_html');
+    \preg_match("/PHP [\d\.]+ Development Server/",$_SERVER['SERVER_SOFTWARE'])) {
   define('DEV_SERVER', true);
+  chdir('public_html');
   if (\preg_match('/\.(?:png|jpg|jpeg|gif|css|js|svg)/', $_SERVER["REQUEST_URI"])) {
     return false;
   }
+} else if (getenv('DEV_SERVER') === "1") {
+  define('DEV_SERVER', true);
+} else {
+  define('DEV_SERVER', false);
 }
 
 require_once __DIR__ . '/../vendor/autoload.php';