Add a tool to help split an image onto two pages

This is mostly for such things as world maps which span both the left and
right pages in an open book

1 files changed, 1 insertions, 0 deletions

diff --git a/Gemfile b/Gemfile
index f971301..ed581f0 100644
--- a/Gemfile
+++ b/Gemfile
@@ -6,4 +6,5 @@ gem "asciidoctor-epub3",
   git: "https://github.com/magentastripe/asciidoctor-epub3",
   branch: "magentastripe"
 gem "epubcheck-ruby"
+gem "mini_magick"
 gem "rghost"