Added meta description for home page

• Added:
- meta description for home page

app/views/layouts/application.html.haml

@@ -38,6 +38,8 @@
       = render 'accounts/meta', account: @account, older_url: nil, newer_url: nil
     - elsif @group
       = render 'groups/meta', group: @group
+    - else
+      %meta{ name: 'description', content: 'Gab is a social network that champions free speech, individual liberty and the free flow of information online. All are welcome.' }/
 
     %title= content_for?(:page_title) ? safe_join([yield(:page_title).chomp.html_safe, title], ' - ') : title