mysql-data:
    class: net.relet.freimap.MysqlDataSource
    host: host
    db: databasename
    user: username
    pass: password
    nodesource: externalsource
    tables:
      links: links
      nodes: nodes

Comments:

• nodesource: Another source for node coordinates is possible
• tables: if your tables are not named "links" and "nodes", you can indicate other names here.