update links

Author: simongravelle

docs/index.html

@@ -82,7 +82,7 @@ <h2>
                         <section>
                             <ul class="icons">
                                 <li>
-                                    <a target="_blank" href="https://github.com/lammpstutorials"
+                                    <a target="_blank" href="https://github.com/gromacstutorials"
                                     class="icon brands fa-github fa-3x">
                                         <span class="label">Github</span>
                                     </a>
@@ -100,7 +100,7 @@ <h2>
                                     </a>
                                 </li>
                                 <li>
-                                    <a target="_blank" href="https://twitter.com/lammpstutorials"
+                                    <a target="_blank" href="https://twitter.com/GravelleSimon"
                                     class="icon brands fa-twitter fa-3x">
                                         <span class="label">Twitter</span>
                                     </a>