Add screenshot and feature description

Author: codingjoe

README.md

@@ -1,6 +1,13 @@
 # DP100 WebApp
 
-A browser interface for the DP100 lab power supply.
+![screenshot](screenshot.png)
+
+A browser interface for the DP100 digital power supply by Alientek.
+
+## Features
+
+- Connect to the DP100 using your browser (no installation required).
+- Histogram of the voltage and current levels.
 
 ## Usage