Discovered a great gem for merging pdf files as an alternative to rmagick/mini-magick, which tends to run into memory/clean-up problems on heroku:
https://github.com/boazsegev/combine_pdf
It is a relatively new gem but appears to work well so far.
https://github.com/boazsegev/combine_pdf
It is a relatively new gem but appears to work well so far.