'No suitable driver' error raised when using Redshift's URL in the manifest

[davidor]

The JDBC URL that appears in Redshift's dashboard starts with jdbc:redshift://... . However, Blueshift expects jdbc:postgresql://... in the manifest file.

When using the first one, Blueshift raises this error when trying to connect to Redshift: Error loading into blueshift java.sql.SQLException: No suitable driver found for jdbc:redshift://...

This is because Blueshift uses the Postgresql driver instead of the Redshift driver.

I think that this is a common problem that users might have. So it may be a good idea to check this in the manifest validation and alert the user with a custom error instead of raising the generic SQLException. What do you think?