Update README.md

Author: manuwei

README.md

@@ -1 +1,4 @@
-"# initialized-pattern-atlas-db" 
+The initialized-pattern-atlas-db container is a postgres database instance that contains data from 
+ 
+ - [a public repo](https://github.com/PatternAtlas/pattern-atlas-content)
+ - [a private repo](https://github.com/PatternAtlas/internal-pattern-atlas-content) - for this, follow the instructions in the readme