This PR adds a partial index for DOIs which makes sure that if the type of a DOI is string then it must be unique. This ensures that there can be multiple null values, but there can only be one of each DOI.
Make sure to run the migration script on the database.
@dylanmcreynolds This PR may not actually be necessary considering that we are making DOIs not required anymore, and allowing duplicate DOIs. So hold off on merging this.
This PR adds a partial index for DOIs which makes sure that if the type of a DOI is string then it must be unique. This ensures that there can be multiple null values, but there can only be one of each DOI.
Make sure to run the migration script on the database.
fixes #99