it should work

Makefile

@@ -1,10 +1,12 @@
 PY?=python3
 PELICAN?=pelican
+PELICANTHEME?=pelican-themes
 PELICANOPTS=
 
 BASEDIR=$(CURDIR)
 INPUTDIR=$(BASEDIR)/content
 OUTPUTDIR=$(BASEDIR)/output
+THEMEDIR=$(BASEDIR)/themes/alchemy
 CONFFILE=$(BASEDIR)/pelicanconf.py
 PUBLISHCONF=$(BASEDIR)/publishconf.py
 
@@ -37,6 +39,7 @@ help:
 	@echo '   make clean                          remove the generated files         '
 	@echo '   make regenerate                     regenerate files upon modification '
 	@echo '   make publish                        generate using production settings '
+	@echo '	  make theme                          add theme                          '
 	@echo '   make serve [PORT=8000]              serve site at http://localhost:8000'
 	@echo '   make serve-global [SERVER=0.0.0.0]  serve (as root) to $(SERVER):80    '
 	@echo '   make devserver [PORT=8000]          serve and regenerate together      '
@@ -72,6 +75,9 @@ devserver-global:
 publish:
 	"$(PELICAN)" "$(INPUTDIR)" -o "$(OUTPUTDIR)" -s "$(PUBLISHCONF)" $(PELICANOPTS)
 
+theme:
+	"$(PELICANTHEME)" --install "$(THEMEDIR)" --verbose
+
 github: publish
 	ghp-import -m "Generate Pelican site" -b $(GITHUB_PAGES_BRANCH) "$(OUTPUTDIR)"
 	git push origin $(GITHUB_PAGES_BRANCH)