<?xml version="1.0" encoding="UTF-8"?>
<doctrine-mapping xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping"
                  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                  xsi:schemaLocation="http://doctrine-project.org/schemas/orm/doctrine-mapping
                  http://doctrine-project.org/schemas/orm/doctrine-mapping.xsd">
                  
    <entity name="ZfcUserDoctrineORM\Entity\User" table="user">

    </entity>

</doctrine-mapping>

<?xml version="1.0" encoding="UTF-8"?>
<doctrine-mapping xmlns="http://doctrine-project.org/schemas/orm/doctrine-mapping"
                  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
                  xsi:schemaLocation="http://doctrine-project.org/schemas/orm/doctrine-mapping
                  http://doctrine-project.org/schemas/orm/doctrine-mapping.xsd">
                  
    <entity name="ZfcUserDoctrineORM\Entity\User" table="`user`">

    </entity>

</doctrine-mapping>

Add backticks to table name
Add backticks to table name

In postgres the table user has a reserved meaning, so we need to add backticks to the table name so that doctrine is able to add quotes to the table name. See https://github.com/ZF-Commons/ZfcUserDoctrineORM/issues/77 and https://github.com/doctrine/dbal/pull/572 for some related issues