Adds extra step in instruction for Database updates with the Maven liquibase:diff goal

[ernesto-butto]

I want to propose an addition to the Documentation, specifically to

https://www.jhipster.tech/development/ , section: Modify your JPA entity (add a field, a relationship, etc.)

If you modify your entity, for example, you add a new field, then, the new field is added to the

config/liquibase/changelog/DATE_added_entity_ENTITY_NAME.xml

So when the liquibase:diff goal is called, and a new changelog is added such as

<changeSet author="poolebu (generated)" id="1618764540135-3" >
    <addColumn tableName="ENTITY_NAME">
        <column name="NEW_COLUMN" type="bit" defaultValueBoolean="true"/>
    </addColumn>
</changeSet>

Then the changesets conflict.

This commit has my proposal of adding an extra step to the instructions for using the workflow.

[gmarziou]

I wonder if this procedure still makes sense with JHipster 7 new feature: incremental changelogs?

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[avdev4j]

I wonder if this procedure still makes sense with JHipster 7 new feature: incremental changelogs?

for records, I guess yes, for people that are < JHipster 7 or still want to have a "manual" solution. Maybe we can link the incremental doc here to suggest using it instead.

[avdev4j]

I covered that in a blog post: https://dev.to/entando/how-to-use-liquibase-to-update-the-schema-of-your-jhipster-application-1cm3

I think it still makes sense to add a note in the documentation.

@poolebu could you please accept the CLA, so I can merge the PR?

[DanielFran]

@poolebu Can you please sign the CLA so we can merge your PR?