Colorize is a gem licensed under the GPLv2, so we can’t use it in GitLab without relicensing GitLab under the terms of the GPL. Rainbow is licensed under the MIT license and does the exact same thing as Colorize, so Rainbow was added in place of Colorize.

The syntax is slightly different for Rainbow vs. Colorize, and was updated in accordance.

The gem is still a dependency of Spinach, so it’s included in the development/test environments, but won’t be packaged with the actual product, and therefore doesn’t require we relicense the product.

An attempt at relicensing Colorize was made, but didn’t succeed as the library owner never responded.

Rainbow library: https://github.com/sickill/rainbow
Relevant issue regarding licensing in GitLab's gems: https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/3775

Performance is improved in two steps:

1. On PostgreSQL an expression index is used for checking lower(email)
   and lower(username).
2. The check to determine if we're searching for a username or Email is
   moved to Ruby. Thanks to @haynes for suggesting and writing the
   initial implementation of this.

Moving the check to Ruby makes this method an additional 1.5 times
faster compared to doing the check in the SQL query.

With performance being improved I've now also tweaked the amount of
iterations required by the User.by_login benchmark. This method now runs
between 900 and 1000 iterations per second.

This ensures any PostgreSQL specific schema changes (e.g. expression
indexes) are created when setting up the database.

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

You should update to 6.0 before proceed with update to higher version.
So its no reason to keep old tasks any more.
It should be still available in 6-0-stable but not in master