Mar 23, 2016 09:04 PM|Mikesdotnetting|LINK
Your summation is correct.
Migrations keep your database in sync with your domain model. When you make a change to the domain model, you "scaffold" a migration, and then execute it. The migration itself is C# code that uses the context to make the required schema changes to the database.
You can read more about them here: https://msdn.microsoft.com/en-gb/data/jj591621.aspx