I updated to 2.0 and ir crashed my whole site. I am also not able to login it. I am getting the following issues in the error log:
<pre style="color: #000000;">[27-Jan-2016 01:37:10 UTC] WordPress database error Duplicate key name 'domain_path' for query ALTER TABLE wp_signups ADD KEY domain_path (domain(140),path(51)) made by require_once('wp-load.php'), require_once('wp-config.php'), require_once('wp-settings.php'), do_action('init'), call_user_func_array, GF_User_Registration->init, GFFeedAddOn->init, GFAddOn->init, GFAddOn->init_frontend, GFFeedAddOn->setup, GFAddOn->setup, GF_User_Registration->upgrade, GFUserSignups::create_signups_table, GFUserSignups::install_signups, dbDelta
We checked your site and it seems to be working fine.
The wordpress database error clearly points where the issue lies, the error indicates the code which does not belong to our theme or plugins.
Can you please check with the plugin author on this.