Merge pull request ossu#345 from tawfiq9009/patch-1

Add two database courses on free-courses.md

Author: ericdouglas

extras/free-courses.md

@@ -152,6 +152,8 @@ Courses | Duration | Effort
 Courses | Duration | Effort
 :-- | :--: | :--:
 [Using Databases with Python](https://www.coursera.org/learn/python-databases) | 5 weeks | 2-3 hours/week
+[Database Systems](https://scs.hosted.panopto.com/Panopto/Pages/Sessions/List.aspx#folderID=%22ed2ee867-9610-4bad-94af-5d12c2ea47cd%22) | - | 27 hours
+[Database Management Essentials](https://www.coursera.org/learn/database-management) | 7 weeks | 4-6 hours/week
 
 ### Cloud Computing