Convert migration file from 4.2 to 5.2
I recently saw Redmine use Rails 5.2.1, which is a good thing.
However, upgrading to Rails 5.2.1 does not simply add it to the Gemfile.
I have migrated the migration files from 4.2 to 5.2, please consider the patch.
The reason for the change: The default id of Rails 3-4 is int, which allows for a maximum of 4.2 billion items.
This is not a big number when using Redmine in large-scale applications.
Need to replace with bigint(20) in id and foreign key.
I tested the patch and confirmed that Redmine works normally after the upgrade.