[$40] "npm run init-db" should init already done migrations

[maxceem]

When we run the TaaS API locally we are running "npm run init-db" to create the DB schema.
The created DB schema already includes all the changes we've done using migrations scripts inside the migrations folder.
But if we run npm run migrate we would get an error, because it would try to apply all the migrations again.
This is bad because we might need to test migrations locally if we are working on some DB updates.

To fix this, when we run "npm run init-db" we have to make sure, that the migrations which are already applied to the current DB schema would not be re-applied again.

To do so I think the best way is:

• when run "npm run init-db" we have to add all the filenames in migration folder to the SequalizeMeta table:
  
• make sure that table is also created
• if a table exists, data should be cleared here and re-populated based on the file list in the migrations directory

[maxceem]

Challenge https://www.topcoder.com/challenges/b636f84b-b92d-4b91-a793-e0808fb399ee has been created for this ticket.

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[maxceem]

@imcaizheng this is open for pickup. You may give it the lowest priority after all other issues.

[maxceem]

Challenge https://www.topcoder.com/challenges/b636f84b-b92d-4b91-a793-e0808fb399ee has been assigned to aaron2017.

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[imcaizheng]

PR created #176

[maxceem]

This task is only needed for local development purposes, so I'm closing it without QA.