in icCube 5.1 there is no Redshift as list of supported JDBC connections.
How to create a data source in icCube on Amazon Redshift ?
A first solution is using the Postgres jdbc driver. Redshift is based on Postgres so it also works (for how long is a good question).
The second is a bit more complicated as you need to add Reshift jdbc driver to icCube. First download jdbc driver from amazon from here, after follow this instructions to add a library to icCube.
Once done you've to configure a new data-source :