Grails migrations and 'Waiting for changelog lock'

Sometimes it may happen that the automatic migrations in a Grails project may come to a hold due to the fact that Liquibase keeps waiting for a changelog lock. At the end this will result in a application that is not going to be deployed.

...
Waiting for changelog lock....
Waiting for changelog lock....
Waiting for changelog lock....
...

To solve this take the following steps:

• Stop the application container (example: Tomcat)
• In the database look for a table called DATABASECHANGELOGLOCK
• In the table there is a record with id=1, change the following values:

locked -> 0
lockgranted -> null
lockedby -> null

• After updating this record start the application container

Notes:
To see who has locked the database (normally the local machine):

select * from DATABASECHANGELOGLOCK;
To update the record
update DATABASECHANGELOGLOCK
set locked=0, lockgranted=null, lockedby=null
where id=1