added the link backfilling functionality

minor improvements/corrections

constants.js

@@ -1,6 +1,6 @@
 const accountsAPIURL = 'https://accounts.spotify.com';
 const baseAPIURL = 'https://api.spotify.com/v1';
-
+const sessionName = 'spotify-manager';
 const stateKey = 'spotify_auth_state';
 
 const scopes = {
@@ -19,6 +19,7 @@ const scopes = {
 module.exports = {
 	accountsAPIURL,
 	baseAPIURL,
+	sessionName,
 	stateKey,
 	scopes
 }