Resolve Schema Merge Conflicts in Rails

Normally, you can run rake db:migrate, and the problem is solved. Here are instructions for when that doesn’t cut it…

Export a SQL backup from the production database into the local development database.

$ psql app-name_development < 2018-01-30-app-name.sql  # or mysql, or sqlite3, or whatever

Rewrite the db/schema.rb file from the local development database.

$ bundle exec rake db:schema:dump

Migrate.

$ bundle exec rake db:migrate