Added documentation for MysqlMq module

Author: ProkopovVitaliy

app/code/Magento/MysqlMq/README.md

@@ -1,3 +1,24 @@
-# MysqlMq
+# Magento_MysqlMq module
 
-**MysqlMq** provides message queue implementation based on MySQL.
+**Magento_MysqlMq** provides message queue implementation based on MySQL.
+
+## Installation
+
+Module creates the following tables:
+
+- `queue` - Table storing unique queues
+- `queue_message` - Queue messages
+- `queue_message_status` - Relation table to keep associations between queues and messages
+
+
+For information about a module installation in Magento 2, see [Enable or disable modules](https://devdocs.magento.com/guides/v2.4/install-gde/install/cli/install-cli-subcommands-enable.html).
+
+## Additional information
+
+For information about significant changes in patch releases, see [2.3.x Release information](http://devdocs.magento.com/guides/v2.3/release-notes/bk-release-notes.html).
+
+### cron options
+
+cron group configuration can be set in `etc/crontab.xml`.
+
+- `mysqlmq_clean_messages` - clean up old messages from database