Instructions are needed for running against mysql data source

[fanis]

Trying to set this up for a Mysql Data Source required some trial and error in the Data Source configuration. It could be useful to others to add to the documentation/readme some notes on that.

After downloading the JDBC Mysql connector and placing it in jdbc-drivers according to the instructions, In Data Source I had to set the Connection Url to jdbc:mysql://[ip]:[port]/[db] but more importantly I had to set the Driver Class Name to com.mysql.cj.jdbc.Driver.

Attempting to Ping the database gives me a ERROR: java.sql.SQLException: SQL String cannot be empty but I can use the Data Source for Reports.

[shzlw]

Add MySQL data source example