Update README.md

README.md

 # spr2021-a1
 
-starter code for A1 for CMSC828D Spring 2021.
+starter code for A1 for CMSC828D Spring 2021 (run using Python 3.5).
 
 You will need the following python packages to run this code: `flask`, `psycopg2`.
+```
+pip install flask psycopg2
+```
 
 To run the server:
 ```