How to perform sql schema migrations in app engine managed vm?
SQL schema migration is a well-known branch of SQL DB administration which is not specific to Cloud SQL, which is mainly different to other SQL systems in how it is deployed and networked. Other than this, you should look up schema migration documentation and articles online to learn how to approach your specific situation. This question is too broad for Stack Overflow as it is, however. Best of luck!
I'm currently using google cloud sql 2nd generation instances to host my database. I need to make a schema change to a table but Im not sure what the best way to do this. 
Ideally, before I deploy using gcloud preview app deploy my migrations will run so the new version of the code is using the latest schema. Also, if I need to rollback to an old version of my app the migrations should run for that point in time. Is there a way to integrate sql schema migrations with my app engine deploys?
My app is app engine managed VM python/flask.