Flarum beta9 中文搜索优化

MySQL 自 5.7 开始支持 FULLTEXT 中文搜寻，重建索引即可

修改 mysql.cnf，加入：

[mysqld]
ngram_token_size=2

修改后需要重建 FULLTEXT 索引

ALTER TABLE flarum_posts DROP INDEX content;
CREATE FULLTEXT INDEX content ON `flarum_posts` (`content`) WITH PARSER ngram;

ALTER TABLE flarum_discussions DROP INDEX title;
CREATE FULLTEXT INDEX title ON `flarum_discussions` (`title`) WITH PARSER ngram;