Redirection after changing the old domain to the new domain in Discourse Forum

Here is the best method used for a full redirection after a domain change.

In the app.yml, at the end add the after_web_config and after_ssl blocks

hooks:
  after_code:
    - exec:
        cd: $home/plugins
        cmd:
          - git clone https://github.com/discourse/docker_manager.git

  after_web_config:
    - replace:
        filename: /etc/nginx/nginx.conf
        from: /sendfile.+on;/
        to: |
          server_names_hash_bucket_size 64;
          sendfile on;
    - file:
        path: /etc/nginx/conf.d/discourse_redirect_1.conf
        contents: |
          server {
            listen 80;
            listen 443 ssl;
            server_name old-domain.com;
            return 301 $scheme://new-domain.com$request_uri;
          }
  after_ssl:
    - replace:
        filename: "/etc/runit/1.d/letsencrypt"
        from: /--keylength/
        to: "-d old-domain.com --keylength"

## Any custom commands to run after building
run:
  - exec: echo "Beginning of custom commands"
  ## If you want to set the 'From' email address for your first registration, uncomment and change:
  ## After getting the first signup email, re-comment the line. It only needs to run once.
  #- exec: rails r "SiteSetting.notification_email='info@unconfigured.discourse.org'"
  - exec: echo "End of custom commands"

It will redirect the old links to the new forums, without a SSL issue.