title: Create database upgrade diff with Liquibase
body: <p>I have two database schema files, both of them are empty. Let's say that there's a version 1 and a version 2 of the database schema in db.v1.sql and db.v2.sql.</p>
  
  <p>I'd like create a diff which will update a database with the schema db.v1.sql to db.v2.sql.</p>
  
  <p>Is Liquibase is capable to do that? 
  Is there another tool to do it from Java?</p>