diff --git a/Dockerfiles/ubuntu2204 b/Dockerfiles/ubuntu2204
index 7690611..03cea6b 100644
--- a/Dockerfiles/ubuntu2204
+++ b/Dockerfiles/ubuntu2204
@@ -40,6 +40,7 @@ pip3 install sympy pyyaml jsonschema
 
 RUN gem install \
 asciidoctor \
+asciidoctor-sail \
 asciidoctor-bibtex \
 asciidoctor-diagram \
 asciidoctor-mathematical \