Create previously_viewed.md

docs/ensembl-help/using-ensembl/viewing-ensembl-data/the_basics/previously_viewed.md

+---
+slug: previously_viewed
+title: Previously viewed
+description: How Ensembl keeps track of the pages you've visited previously
+related_articles:
+  - href: ../entity_viewer/entity-viewer.md
+  - href: ../genome-browser/browser.md
+tags:
+  - gene
+status: draft
+---
+
+![](../../../../placeholder.jpg)