Save migrations file on db (#215)

* Revert "Migration sql changes (#199)"

This reverts commit 12c834469c.

* Save migrate file on db

* Add message on migration error in lamassu-update

migrations/1514981004673-add_serial_to_logs.js

@@ -1,9 +1,7 @@
 const db = require('./db')
 
 exports.up = function (next) {
-  const sql = [
-    db.addColumn('logs', 'serial', 'integer not null default 0')
-  ]
+  const sql = ['alter table logs add column serial integer not null default 0']
   db.multi(sql, next)
 }