<%= form_tag("/person", :method => "get") do %>
<%= search_field_tag(:search, params[:search]) %>
<%= submit_tag("Search") %>
<% end %>
But why, after submit form url is:
Your browser constructs the URL from the form. It doesn't know
anything about routes so will always just use the URL specified in the
form's action attribute, either appending the query string or sticking
it in the request body depending on whether it's a get or a post.