plan

type ExecuteResult struct {
	Completed int
	Total     int
	Error     error // nil if all steps succeeded
	FailStep  int   // which step failed (0 if none)
}

type Plan struct {
	Name      string // filename without directory
	FromHash  string
	ToHash    string
	CreatedAt time.Time
	Steps     []*Step
}

type Step struct {
	Index       int
	Type        string // e.g. "create_table", "add_column"
	Description string
	Tx          bool // whether to run in a transaction
	SQL         string
}