Help migrate our app from Heroku to Digital Ocean

Project status:
We have built a Ruby App (v 2.2.1) using ElasticSearch / Redis / Puma / Sidekiq / etc.
We are using Postgres DBB. The website is live and hosted on Heroku.

Work to be done:

1/ Share your methodology in a written manner to explain how to migrate the existing app from Heroku to Digital Ocean: create 2 environments Staging / Production, migrate the existing database Postgres, link the app to the right domain name, etc. Additional constraint, we would like to make use of Dokku (Dokker/Ubuntu) to make it easy and smooth for us to deploy any changes at a later stage.

2/ Once the process is clear and that we agree on it, deploy the changes.

3/ Potentially we will be looking for some infogerance in the future too.

How to work with us:
We expect from you regular written feedback and smooth communication and respect the deadlines. We will provide you all the support you need to help you achieve the project in due time.
We are a startup, we need to move fast.

Deadlines: 4 days after the contract has been signed.