Warn before approving paper which already exists #132
Description
In the admin dashboard, it is possible to approve a paper while other approved papers with the same metadata exist; causing duplication of papers. We can prevent this by adding a warning if during edit we detect
- The paper has been approved
- At least one paper with the same metadata ("similar paper") exists which is approved
- The "note" field is empty / not unique
- The replace option(s) is/are not checked.