Moses
This is specialization of David Dollar's valkyrie gem. It's been modified for the purpose of migrating a SQL Server database to PostgreSQL.
Assumptions
It assumes an empty PostgreSQL (destination) database with schema that matches the SQL Server (source) database. This can be accomplished in a Rails app by updating its database.yml file to point to the Postgres database and running bundle exec rake db:drop db:create db:schema:load in whichever environment you want to use.
Usage
Since this is not a gem but just a set of scripts, you'll need to clone the code to use it:
git clone git@github.com:molawson/moses.git
Once you have a SQL Server database that you want to migrate to Postgres and an empty Postgres database with the right schema (like described above), you need to create a database.yml file in the config/ directory of this library. There is an existing config/database.example.yml file that you can use as a template. Fill out the database.yml file with the credientials of your source and destination databases.
Then, from the root directory of this library, run:
bundle install
bundle exec ./bin/moses
You'll see a progress bar for each table while it's being migrated.