adds a 'status' command that checks for pending migrations.

[blunckr]

This adds a new command called 'status', that you run like this: go run example/*.go status. If there are no pending migrations, it will print a message indicating that migrations are up to date, and return nil. If there are pending migrations, it will return an error with the message indicating how many are pending. If things are set up as described in the example dir, this will also cause the program to exit with status 1.

This is useful in deployment, for example, in kubernetes, new pods can use this as a check to determine if they are ready to start receiving traffic.

[blunckr]

Oh, I just saw that someone else has already opened a pr that also adds a status command. though it seems like it's intended for a different purpose.