Rails 4 Nested form with devise logs me out on update - ruby-on-rails

Question

I have a nested form with the parent model built with devise and the child model without devise. I'm working on the edit form which has the user model fields and nested inside them expert model fields. The update/save works but logs me out and gives me an error saying "You need to sign in or sign up before continuing"
When I sign back in I see that the fields have been updated correctly. I would like it to not sign me out and show me the updated Edit page upon submitting the form.
User model - built with devise.
class User < ActiveRecord::Base
// some stuff
has_one :expert
accepts_nested_attributes_for :expert, :update_only => true
// more stuff
Expert model - built withOUT devise.
class Expert < ActiveRecord::Base
belongs_to :user
User controller:
before_action :set_user, only: [:show, :edit, :update, :destroy]
before_filter :authenticate_user!, :only => [:show, :edit]
def edit
#user = User.friendly.find(params[:id])
#title = "Edit Profile"
end
def update
respond_to do |format|
if #user.update(user_params)
format.html { redirect_to #user, notice: 'User was successfully updated.' }
format.json { head :no_content }
else
format.html { render action: 'edit' }
format.json { render json: #user.errors, status: :unprocessable_entity }
end
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_user
#user = User.friendly.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def user_params
params.require(:user).permit(:id, :name, :email, :phone, :password, :role, :expert_attributes => [:id, :Location])
end
end
Expert controller:
def edit
#expert = Expert.find(params[:id])
#title = "Edit Expert Profile"
end
Edit user view form partial:
<%= form_for(#user) do |f| %>
<% if #user.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#user.errors.count, "error") %> prohibited this user from being saved:</h2>
<ul>
<% #user.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :Name %><br>
<%= f.text_field :name, :class => "form-control" %>
</div>
<div class="field">
<%= f.label :Email %><br>
<%= f.text_field :email, :class => "form-control" %>
</div>
<div class="field">
<%= f.label :Phone %><br>
<%= f.text_field :phone, :class => "form-control" %>
</div>
<div class="field">
<%= f.label :Password %><br>
<%= f.text_field :password, :class => "form-control" %>
</div>
<div class="field">
<%= f.fields_for :expert do |e| %>
<%= e.label :Location %><br />
<%= e.text_field :Location %>
<% end %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>

Answer 1

In your UsersController, you should add :update to the authenticate_user! filter:
before_filter :authenticate_user!, :only => [:show, :edit, :update]