make for manually clearing the caches

Author: dsweber2

DEVELOPMENT.md

@@ -35,6 +35,8 @@ R -e 'devtools::document()'
 R -e 'pkgdown::build_site()'
 ```
 
+Note that sometimes the caches from either `pkgdown` or `knitr` can cause difficulties. To clear those, run `make`, with either `clean_knitr`, `clean_site`, or `clean` (which does both).
+
 If you work without R Studio and want to iterate on documentation, you might
 find [this
 script](https://gist.github.com/gadenbuie/d22e149e65591b91419e41ea5b2e0621)

Makefile

@@ -0,0 +1,14 @@
+##
+# epipredict docs build
+#
+
+# knitr doesn't actually clean it's own cache properly; this just deletes any of
+# the article knitr caches in vignettes or the base
+clean_knitr:
+	rm -r *_cache; rm -r vignettes/*_cache
+clean_site:
+	Rscript -e "pkgdown::clean_cache(); pkgdown::clean_site()"
+# this combines 
+clean: clean_knitr clean_site
+
+# end