static images in docs + small changes

Author: RedHeadphone

CONTRIBUTING.md

@@ -24,6 +24,7 @@ To run & test codeforces-readme-stats, you need to follow a few simple steps:-
 1.  Fork the repository and clone the code to your local machine.
 2.  Run `npm install` in the repository root.
 3.  Run the command `npm run dev` to start the development server at <http://localhost:3000>.
+4.  To run the development server for docs use command `mkdocs serve` (setup it using command `pip install mkdocs mkdocs-material`)
 
 ## Themes Contribution
 

README.md

@@ -27,7 +27,7 @@ Simply copy the code below, paste it into your `README.md`, and change the usern
 Preview:
 
 <p align="center">
-  <img alt="Codeforces Stats" src="https://codeforces-readme-stats.vercel.app/api/card?username=redheadphone" />
+  <img alt="Codeforces Stats" src="./docs/images/static/card.svg" />
 </p>
 
 Congratulation! You are now showing your Codeforces stats on your profile!
@@ -49,7 +49,7 @@ Rating badge can also be added to your `README.md`, by coping and pasting the co
 Preview:
 
 <p align="center">
-  <img alt="Codeforces Badge" style="height:30px" src="https://codeforces-readme-stats.vercel.app/api/badge?username=redheadphone" />
+  <img alt="Codeforces Badge" style="height:30px" src="./docs/images/static/badge.svg" />
 </p>
 
 ## Contributing