use podman container to build

Makefile

@@ -2,17 +2,13 @@
 
 HTMLS = $(patsubst notebooks/%.ipynb,html/%.html,$(wildcard notebooks/*.ipynb))
 
-badmathjax = "file:\/\/\/usr\/share\/javascript\/mathjax\/MathJax.js?config=TeX-AMS_CHTML-full,Safe"
-goodmathjax = "https:\/\/cdn.jsdelivr.net\/npm\/mathjax@2\/MathJax.js?config=TeX-AMS_CHTML"
-
 all: $(HTMLS)
 
 clean:
 	rm -r html
 
 html/%.html: notebooks/%.ipynb | html
-	jupyter nbconvert --to html $< --output $@ --output-dir=.
-	sed -i 's/$(badmathjax)/$(goodmathjax)/' $@
+	podman run -it --rm -v .:/home/sage/eulerbooks --userns=keep-id sagemath/sagemath:latest jupyter nbconvert --to html eulerbooks/$< --output $@ --output-dir=eulerbooks/
 
 html:
 	mkdir -p html