Use MySQL’s utf8mb4 instead of utf8

See http://mathiasbynens.be/notes/mysql-utf8mb4 for more information.

.gitattributes

@@ -1 +1,2 @@
-* crlf=input
+# Automatically normalize line endings for all text-based files
+* text=auto

database.sql

@@ -1,9 +1,10 @@
+# Why you should use `utf8mb4` instead of `utf8`: http://mathiasbynens.be/notes/mysql-utf8mb4
 CREATE TABLE `redirect` (
-	`slug` varchar(14) collate utf8_unicode_ci NOT NULL,
-	`url` varchar(620) collate utf8_unicode_ci NOT NULL,
+	`slug` varchar(14) collate utf8mb4_unicode_ci NOT NULL,
+	`url` varchar(620) collate utf8mb4_unicode_ci NOT NULL,
 	`date` datetime NOT NULL,
 	`hits` bigint(20) NOT NULL default '0',
 	PRIMARY KEY (`slug`)
-) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci COMMENT='Used for the URL shortener';
+) ENGINE=MyISAM DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci COMMENT='Used for the URL shortener';
 
 INSERT INTO `redirect` VALUES ('a', 'https://github.com/mathiasbynens/php-url-shortener', NOW(), 1);

index.php

@@ -21,7 +21,7 @@
 		} else {
 
 			$db = new MySQLi(MYSQL_HOST, MYSQL_USER, MYSQL_PASSWORD, MYSQL_DATABASE);
-			$db->set_charset('utf8');
+			$db->set_charset('utf8mb4');
 
 			$escapedSlug = $db->real_escape_string($slug);
 			$redirectResult = $db->query('SELECT url FROM redirect WHERE slug = "' . $escapedSlug . '"');

shorten.php

@@ -28,7 +28,7 @@ function getNextShortURL($s) {
 }
 
 $db = new mysqli(MYSQL_HOST, MYSQL_USER, MYSQL_PASSWORD, MYSQL_DATABASE);
-$db->set_charset('utf8');
+$db->set_charset('utf8mb4');
 
 $url = $db->real_escape_string($url);