updated readme

Author: gopalbala

README.md

@@ -53,7 +53,7 @@ We can have a service that can generate identifiers and distribute them to servi
 
 https://blog.twitter.com/engineering/en_us/a/2010/announcing-snowflake.html 
 
-Other references
+Other references  
 https://github.com/sony/sonyflake 
 https://instagram-engineering.com/sharding-ids-at-instagram-1cf5a71e5a5c  
 https://docs.mongodb.com/manual/reference/method/ObjectId/