How to migrate database with git?
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I do website development (primarily Drupal base sites) and have a workflow with:

 1. many developers working on their **Local machines**
 1. developers use git to merge their changes on a **Development machine**
 1. when the dev site hits a stable point, we push to a **Staging server** for the client to review
 1. and finally we make releases to the **Production server**

And git is moving the files nicely back and forth.  My question is how do I one-up this and use git to migrate the database along with the files?

And once I am able to move dev databases up the ladder, how do I merge development databases with the active production database?