docs: fix a dead link (#572)

docs/organization/overview.md

@@ -17,7 +17,7 @@ Casdoor provides multiple password storage algorithms that can be selected on th
 |:--:|:--:|--|:--:|
 |plain|-|The password will be stored in cleartext. (default)|-|
 |salt|[SHA-256](https://github.com/casdoor/casdoor/blob/master/cred/sha256-salt.go)|[SHA-256](https://www.n-able.com/blog/sha-256-encryption) is a patented cryptographic hash function that outputs a value that is 256 bits long.|-|
-|md5-salt|[MD5](https://github.com/casdoor/casdoor/blob/master/cred/md5-user-salt.go)|The [MD5 message-digest algorithm](https://en.wikipedia.org/wiki/MD5) is a cryptographically broken but still widely used hash function producing a 128-bit hash value. |[Discuz!](https://www.discuz.net/)|
+|md5-salt|[MD5](https://github.com/casdoor/casdoor/blob/master/cred/md5-user-salt.go)|The [MD5 message-digest algorithm](https://en.wikipedia.org/wiki/MD5) is a cryptographically broken but still widely used hash function producing a 128-bit hash value. |[Discuz!](https://www.discuz.vip/)|
 |bcrypt|[bcrypt](https://github.com/casdoor/casdoor/blob/master/cred/bcrypt.go)|[bcrypt](https://en.wikipedia.org/wiki/Bcrypt) is a password-hashing function and is used to hash and salt passwords securely.|[Spring Boot](https://spring.io/projects/spring-boot), [WordPress](https://stackoverflow.com/questions/1045988/what-type-of-hash-does-wordpress-use)|
 |pbkdf2-salt|[SHA-256 and PBKDF2](https://github.com/casdoor/casdoor/blob/master/cred/pbkdf2-salt.go)|[PBKDF2](https://en.wikipedia.org/wiki/PBKDF2) is a simple cryptographic key derivation function that is resistant to dictionary attacks and rainbow table attacks. It was originally implemented in Casdoor for the Keycloak syncer. Select this option if you are importing users using the Keycloak syncer.|[Keycloak](http://keycloak.org/)|