Added MySQL PW instructions

docs/reset_pw.md

@@ -13,6 +13,47 @@ bash mailcow-reset-admin.sh
 
 ```
 
-## MySQL Passwords
+## Reset MySQL Passwords
 
-Please refere to our (MySQL section)(mysql/#reset-mysql-passwords) for instructions on resetting your MySQL passwords.
+Stop the stack by running `docker-compose stop`.
+
+When the containers came to a stop, run this command:
+
+```
+docker-compose run --rm --entrypoint '/bin/sh -c "gosu mysql mysqld --skip-grant-tables & sleep 10 && mysql -hlocalhost -uroot && exit 0"' mysql-mailcow
+```
+
+### 1\. Find database name
+
+```
+MariaDB [(none)]> show databases;
++--------------------+
+| Database           |
++--------------------+
+| information_schema |
+| mailcow_database   | <=====
+| mysql              |
+| performance_schema |
++--------------------+
+4 rows in set (0.00 sec)
+```
+
+### 2\. Reset one or more users
+
+Both "password" and "authentication_string" exist. Currently "password" is used, but better set both.
+
+```
+MariaDB [(none)]> SELECT user FROM mysql.user;
++--------------+
+| user         |
++--------------+
+| mailcow_user | <=====
+| root         |
++--------------+
+2 rows in set (0.00 sec)
+
+MariaDB [(none)]> FLUSH PRIVILEGES;
+MariaDB [(none)]> UPDATE mysql.user SET authentication_string = PASSWORD('gotr00t'), password = PASSWORD('gotr00t') WHERE User = 'root' AND Host = '%';
+MariaDB [(none)]> UPDATE mysql.user SET authentication_string = PASSWORD('mookuh'), password = PASSWORD('mookuh') WHERE User = 'mailcow' AND Host = '%';
+MariaDB [(none)]> FLUSH PRIVILEGES;
+```