Support for templates was dropped in Prawn 0.13.0, disabled by default in 0.14.0, and extracted in 0.15.0.
This gem includes the extracted templates code, which is completely unsupported, but provides the old functionality that was in Prawn 0.12.0 for years.
Templates were originally written by James Healy, but are no longer actively maintained by anyone. Use at your own risk, or volunteer to help maintain the code on the Prawn Mailing list:
https://groups.google.com/forum/#!forum/prawn-ruby
Keep in mind the reason that this gem was extracted is because the code is very buggy! For a list of old issues that were affecting it, see Prawn's tracker: