added credentials file

.gitignore

@@ -1,6 +1,4 @@
 backend/node_modules
-backend/credentials.js
-# See https://help.github.com/articles/ignoring-files/ for more about ignoring files.
 
 # dependencies
 /node_modules

backend/credentials.js

@@ -0,0 +1,2 @@
+// Write your own mongoDBatlas credentials here
+module.exports = '';