Require explicit value of true for ENV variables in config

services/web/config/settings.defaults.coffee

@@ -256,7 +256,7 @@ module.exports =
 	
 	# Should we allow access to any page without logging in? This includes
 	# public projects, /learn, /templates, about pages, etc.
-	allowPublicAccess: if process.env["SHARELATEX_ALLOW_PUBLIC_ACCESS"]? then true else false
+	allowPublicAccess: if process.env["SHARELATEX_ALLOW_PUBLIC_ACCESS"] == 'true' then true else false
 	
 	# Maximum size of text documents in the real-time editing system.
 	max_doc_length: 2 * 1024 * 1024 # 2mb