Add db migrations

[vminkobin]

Library for migrations code from this pr https://github.com/trustwallet/backend/pull/2331

Additionally added method which reads migration params from env vars and runs migrations, so it can be used in services like

package main

import (

	"github.com/trustwallet/go-libs/database"

	"github.com/sirupsen/logrus"
)

func main() {
	log := logrus.New()
	if err := database.RunFromEnv(log); err != nil {
		log.Errorf("run migrations: %v", err)
	}
}

[tw-dmy]

we can simplify this a bit, and use migrate.New("file://...", "connection string") instead of initializing db connection with sql.Open and then passing it no NewWithDatabaseInstance.

[tw-dmy]

why not setting these fields when initializing MigrationRunner? i.e.

runner := &MigrationRunner{
    filesDir: defaultFilesDir,
    logger:  &noopLogger{},
}

[tw-dmy]

I think it's better to have duplicated prefixes in the constants below ("MIGRATION_DSN", "MIGRATION_OPERATION"), rather than having a method to concatenate them. It will be much more readable, and easier to search where an env var is used, i.e. when you see an env definition in a deployment config, and would like to know in which package it's used. If env vars defined as a full name, you can just search across all repos and find it.

[tw-dmy]

[minor] this is required only for "force" operation, in other cases it's just ignored.

[vminkobin]

yes and error will occur here only when related env var is set

[vminkobin]

@tw-dmy thanks for the comments, all resolved