Added twitter card

index.html

@@ -10,6 +10,10 @@
   <link rel="stylesheet" href="web/default.min.css">
   <script src="web/highlight.min.js"></script>
   <script src="web/script.js"></script>
+  <meta name="twitter:card" content="summary_large_image">
+  <meta name="twitter:title" content="Comprehensive Python Cheatsheet">
+  <meta name="twitter:description" content="Pythonic cheatsheet about Python programming language, covering almost all parts of Python 3 and also a few of the most useful third party libraries.">
+  <meta name="twitter:image" content="https://gto76.github.io/python-cheatsheet/web/image_888.jpeg">
 </head>
 
 <style>