add favicon to the home page

Author: lpmi-13

index.html

@@ -5,6 +5,7 @@
     <meta charset="UTF-8">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <meta name="description" content="Raft is a consensus algorithm that is designed to be easy to understand.">
+    <link rel="icon" type="image/x-icon" href="logo/favicon.ico" >
     <!-- The next line authorizes Diego to use the Google Search Console on this site. -->
     <meta name="google-site-verification" content="aRKNQn2I0UXp0xfA1c6Hz0d_fiWqhhAGfher0aZRL3g" />
     <link rel="stylesheet" href="https://netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css" integrity="sha384-dkTxiR4Mv8i0ubTj0fsgTCmhYmOtrc0o6rdrEO6hDZs9cAifak0Y2VVL2cecWHLQ" crossorigin="anonymous" >