Update elastic search content

* Update 100-elastic-stack.md

* Update content/roadmaps/102-devops/content/107-monitoring/102-logs-management/100-elastic-stack.md

Co-authored-by: Kamran Ahmed <kamranahmed.se@gmail.com>

content/roadmaps/102-devops/content/107-monitoring/102-logs-management/100-elastic-stack.md

@@ -2,7 +2,12 @@
 
 Elastic Stack is a group of open source products comprised of Elasticsearch, Kibana, Beats, and Logstash and more that help store, search, analyze, and visualize data from various source, in different format, in real-time.
 
+* `Elastic Search` - Search and analytics engine
+* `Logstash/fluentd` - Data processing pipeline
+* `Kibana` - Dashboard to visualize data
+
 <ResourceGroupTitle>Free Content</ResourceGroupTitle>
-<BadgeLink colorScheme='blue' badgeText='Official Website' href='https://www.elastic.co/elastic-stack/'>Elastic Stack Website</BadgeLink>
-<BadgeLink colorScheme='blue' badgeText='Official Docs' href='https://www.elastic.co/guide/index.html'>Official Docs</BadgeLink>
-<BadgeLink colorScheme='blue' badgeText='Features List' href='https://www.elastic.co/elastic-stack/features'>Elastic Stack features</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Official Website' href='https://www.elastic.co/elastic-stack/'>Elastic Stack Website</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Official Docs' href='https://www.elastic.co/guide/index.html'>Official Docs</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Features List' href='https://www.elastic.co/elastic-stack/features'>Elastic Stack features</BadgeLink>
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://logz.io/blog/fluentd-logstash/'>Logstash vs Fluentd</BadgeLink>