add optional feature for sftp webroot access, wip

.env.sample

@@ -25,4 +25,9 @@ COMPOSE_FILE="compose.yml"
 #REDIRECT_TYPE=permanent
 
 # Optionally handle all URL requests using a single file (commonly index.html)
-#SINGLE_PAGE_SITE_HANDLER=/index.html
+#SINGLE_PAGE_SITE_HANDLER=/index.html
+
+# Enable an SSH server to allow SFTP uploads to the web root
+#COMPOSE_FILE="$COMPOSE_FILE:compose.sftp.yml"
+#SECRET_SSH_PASSWORD_VERSION=v1
+#SSH_PORT="2222" # this doesn't work yet, maybe an abra bug?