modified the column type LearningObject id (int->str) to DSpace 6.3 and download system ( retrieve link)

Adding "times_blocked" to user in order to keep track of how many times has the selected users been blocked (blocked or banished).

Adding "state", "suspended at" and "reactivated_at" columns to User to allow blocking and banishing mechanisms of users.

Modifying complaint_reason table, setting a new column "status" to define its state (active or inactive), as well as giving it a controller to allow users that has "editor" or  "administrator" as role to create and update its entries