Add username to admin users index

app/datatables/user_datatable.rb

@@ -31,6 +31,7 @@ class UserDatatable < AjaxDatatablesRails::Base
         confirmed_at: record.confirmed_at,
         email:        record.email,
         name:         record.name,
+        username:     record.username,
         attended:     record.attended_count,
         roles:        record.roles.any? ? show_roles(record.get_roles) : 'None',
         view_url:     admin_user_path(record),

app/views/admin/users/index.html.haml

@@ -14,9 +14,9 @@
       %thead
         %th{ width: '0' } ID
         %th{ width: '0' } Confirmed?
-        %th{ width: '50%' } Name
-        %th{ width: '0' } Email
-        %th{ width: '0' } Username
+        %th{ width: '30%' } Name
+        %th{ width: '15%' } Email
+        %th{ width: '15%' } Username
         %th{ width: '0' } Conferences Attended
         %th{ width: '50%' } Roles
         %th{ width: '0' } Actions