add mixpanel events for signup page

app/views/forum_topics/show.html.erb

@@ -38,11 +38,11 @@
 
 <%= render "secondary_links" %>
 
-<%= content_for(:page_title) do %>
+<% content_for(:page_title) do %>
   Forum - <%= @forum_topic.title %> - <%= Danbooru.config.app_name %>
 <% end %>
 
-<%= content_for(:html_header) do %>
+<% content_for(:html_header) do %>
   <%= auto_discovery_link_tag(:atom, {format: :atom}, {title: @forum_topic.title}) %>
 
   <script>

app/views/posts/index.html.erb

@@ -69,7 +69,7 @@
   <% end %>
 <% end %>
 
-<%= content_for(:html_header) do %>
+<% content_for(:html_header) do %>
   <%= tag.link href: posts_path(format: "atom", tags: params[:tags]), rel: "alternate", title: "ATOM", type: "application/atom+xml" %>
   <%= tag.link rel: "prefetch", href: next_page_url, as: "html", crossorigin: "use-credentials" %>
   <%= tag.link rel: "next", href: next_page_url %>

app/views/users/_sign_up_notice.html.erb

@@ -1,4 +1,17 @@
 <div class="ui-corner-all ui-state-highlight" id="sign-up-notice">
-  <h1>Like the site? <%= link_to "Sign up for a free basic account!", new_user_path %></h1>
+  <h1>Like the site? <%= link_to "Sign up for a free basic account!", new_user_path, id: "sign-up-link" %></h1>
   <p><%= link_to "No thanks", "#", :id => "hide-sign-up-notice" %></p>
 </div>
+
+<% content_for(:html_header) do %>
+  <script>
+    $(function() {
+      $("#sign-up-link").click(function() {
+        window.Danbooru.mixpanelEvent("clicked sign up");        
+      });
+      $("#hide-sign-up-notice").click(function() {
+        window.Danbooru.mixpanelEvent("hide sign up notice");        
+      });
+    })
+  </script>
+<% end %>

app/views/users/_upgrade_notice.html.erb

@@ -3,7 +3,7 @@
   <p><%= link_to "No thanks", "#", :id => "hide-upgrade-account-notice" %></p>
 </div>
 
-<%= content_for(:html_header) do %>
+<% content_for(:html_header) do %>
   <script>
     $(function() {
       $("#goto-upgrade-account").click(function() {