The connectionStringConfigPath parameter is used in conjuction with the Connection parameter. The Connection parameter specifies the name of the connection string.
This is an example of the migrate task:
<Migrate Database="sqlserver2012"
Connection="SRVConnectionString"
ConnectionStringConfigPath="db.config"
Target="./Migrations/bin/Debug/Migrations.dll">
</Migrate>
And this is the db.config file:
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
<connectionStrings>
<clear />
<add name="SRVConnectionString" connectionString="server=SQLEXPRESS;uid=test;pwd=test;database=Test"/>
</connectionStrings>
</configuration>
I will update the wiki with this example.