Okay, after asking the question the answer popped into my head.
Instead of the
search_form_for helper I'm now just using the
form_tag helper in the following way:
<%= form_tag search_path, method: :get do %> <%= text_field_tag :q, params[:q] %> <%= end %>
and in the search action I just do:
q = params[:q] @works = Work.search(name_cont: q).result @projects = Project.search(name_cont: q).result @users = User.search(name_cont: q).result
This works for me. I hope this also helps someone else.