Cool idea! I am also german and because of the unnecessary 1 star review i give you 5 stars. The problem i encounter at the moment is I can not get it run on my server. Im using 1.21.1 paper.

[12:01:31 ERROR]: [STDERR] [com.mysql.jdbc.Driver] Loading class `com.mysql.jdbc.Driver'. This is deprecated. The new driver class is `com.mysql.cj.jdbc.Driver'. The driver is automatically registered via the SPI and manual loading of the driver class is generally unnecessary.
[12:01:31 WARN]: com.mysql.cj.jdbc.exceptions.CommunicationsException: Communications link failure
[12:01:31 WARN]:
[12:01:31 WARN]: The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.

[12:01:31 WARN]: [Postfach] Plugin Postfach v1.3 generated an exception while executing task 3
java.lang.NullPointerException: Cannot invoke "java.sql.Connection.prepareStatement(String)" because the return value of "v.v.v.g.getConnection()" is null

I havent tested it yet but it looks great. As a dev myself, I think that it is really really inpolite to give only one Star just because of a rule or because you cant use Google translate. Developing a plugin is hard work and he doesnt even ask for money to use this plugin.

This is an English forum and therefore you should use English (see rules). The code is also expandable stay tuned