Added preview picture to readme

README.md

@@ -1,4 +1,6 @@
-This is a simple responsive math calculator built using react js
+![Preview of light theme](https://github.com/ibnzUK/ReactCalc/blob/master/calcLight.png)
+
+This is a simple responsive math calculator built using react js with dark or light theme
 
 ## Community codders, please commit
 
@@ -12,5 +14,5 @@ Feel free to add extra functions or improvements, This helps me to more familiar
 * copy project to your directory ( git clone https://github.com/ibnzUK/ReactCalc.git )
 * navigate to _ReactCalc_ project directory
 * make sure you have node.js installed on your machine
-* npm install
-npm run start
+* install project packages (npm install)
+* start project (npm run start)