DOP-1791 Pushless staging: only install mongodb if not already installed on local comp (#101)

* test deploy

* commit

* clean up

* clean up

* clen up

* clen up

Author: madelinezec

Makefile

@@ -9,7 +9,7 @@ MAKEFLAGS += --silent
 # $(MAKECMDGOALS) is the list of "targets" spelled out on the command line
 stagel: 
 	git clone --quiet https://github.com/mongodb/snooty-scripts.git build_scripts
-	@ cd build_scripts && npm install
+	@ cd build_scripts && npm list mongodb || npm install mongodb
 	@ source ~/.config/.snootyenv && node build_scripts/app.js $(filter-out $@,$(MAKECMDGOALS))
 	@ rm -rf build_scripts