Add content to ETL (#2647)

* Update 101-etl-datawarehouses.md

* Add content to ETL datawarehouses

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

content/roadmaps/114-software-architect/content/109-working-with-data/101-etl-datawarehouses.md

@@ -1 +1,12 @@
-# Etl datawarehouses
+# ETL Datawarehouses
+
+In the world of data warehousing, if you need to bring data from multiple different data sources into one, centralized database, you must first:
+
+* **EXTRACT** data from its original source
+* **TRANSFORM** data by deduplicating it, combining it, and ensuring quality, to then
+* **LOAD** data into the target database
+
+ETL tools enable data integration strategies by allowing companies to gather data from multiple data sources and consolidate it into a single, centralized location. ETL tools also make it possible for different types of data to work together.
+
+<BadgeLink colorScheme='yellow' badgeText='Read' href='https://www.snowflake.com/guides/what-etl'>What is ETL?</BadgeLink>
+<BadgeLink badgeText='Watch' href='https://www.youtube.com/watch?v=OW5OgsLpDCQ'>ETL explained</BadgeLink>