Impossible to add a user (2.0)

[sjcqs]

Current behavior / Resultado actual / Résultat actuel

When a new user is added:
SQLSTATE[23000]: Integrity constraint violation: 1062 Duplicate entry '' for key 'UNIQ_8D93D649A0D96FBF'

Expected behavior / Resultado esperado / Résultat attendu

The user should be correctly added.

Steps to reproduce / Pasos para reproducir / Étapes pour reproduire

Create a new user.

Chamilo Version / Versión de Chamilo / Version de Chamilo

2.0

Useful part of the stacktrace:

at DoctrineORMEntityManager_000000005d8569f90000000058711e67e5139c916d21af4abfe5ffe5dd20d49e->flush()
 in /var/www/html/vendor/friendsofsymfony/user-bundle/FOS/UserBundle/Doctrine/UserManager.php line 100
at FOS\UserBundle\Doctrine\UserManager->updateUser(object(User), true)
 in /var/www/html/main/inc/lib/usermanager.lib.php line 405

[jmontoyaa]

Fixed. Reinstall or execute manually:

DROP INDEX UNIQ_8D93D649A0D96FBF ON user;