Dealing has_one and singular resource with nested resource - ruby-on-rails

Question

I have a User model, which has_one prestataire and has_one employeur. Previously on stackoverflow, someone advised me to declare singular resources, like:
resources :users do
resource: employeur
resource: prestataire
end
Instead of:
resources :users do
resources: employeurs
resources: prestataires
end
Thanks to rails, I didn't had to singularize all my controllers and views name files. Yet, when I create a user and am redirected to the employeur form, I get undefined method `user_employeurs_path', which is right since I only have a user_employeur_path. But I didn't ask for the plural in my user controller. Rails indicates that this NoMethodError happens in the first line of my employeur form <%= form_for [#user, #employeur] do |f| %>, where one is redirected when a user is saved.
class UsersController < ApplicationController
#TODO index user doit être suprimé quand inutile pour dev
def index
#users = User.all
end
def show
#user = User.find(params[:id])
end
def new
#user = User.new
end
# GET /users/1/edit
def edit
#user = User.find(params[:id])
end
# POST /users
# POST /users.json
def create
#user = User.new(user_params)
respond_to do |format|
if #user.save
if params[:commit] == 'Prestataire'
format.html { redirect_to new_user_prestataire_path(user_id: #user), notice: "Renseignez vos informations d'employeur" }
format.json { render action: 'show', status: :created, location: #user }
else
format.html { redirect_to new_user_employeur_path(user_id: #user), notice: "Renseignez vos informations de prestataire" }
format.json { render action: 'show', status: :created, location: #user }
end
else
format.html { render action: 'new' }
format.json { render json: #user.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /users/1
# PATCH/PUT /users/1.json
def update
#user = User.find(params[:id])
respond_to do |format|
if #user.update(user_params)
if params[:commit] == 'Prestataire'
format.html { redirect_to new_user_prestataire_path(user_id: #user), notice: 'User was successfully updated.' }
format.json { head :no_content }
else
format.html { redirect_to new_user_employeur_path(user_id: #user), notice: "User was successfully updated." }
format.json { head :no_content }
end
else
format.html { render action: 'edit' }
format.json { render json: #user.errors, status: :unprocessable_entity }
end
end
end
# DELETE /users/1
# DELETE /users/1.json
def destroy
#user = User.find(params[:id])
#user.destroy
respond_to do |format|
format.html { redirect_to users_url }
format.json { head :no_content }
end
end
private
def user_params
params.require(:user).permit(:email, :password, :password_confirmation, :surname, :forename, :civility, :phone)
end
end
User form:
<%= 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 :civility, 'Titre de civilité: ' %><br>
<%= f.text_field :civility %>
</div>
<div class="field">
<%= f.label :forename, 'Prénom: ' %><br>
<%= f.text_field :forename %>
</div>
<div class="field">
<%= f.label :surname, 'Nom de famille: ' %><br>
<%= f.text_field :surname %>
</div>
<div class="field">
<%= f.label :email, 'Email: ' %><br>
<%= f.text_field :email %>
</div>
<div class="field">
<%= f.label :password, 'Mot de passe: ' %><br>
<%= f.password_field :password, size: 40 %>
</div>
<div class="field">
<%= f.label :password_confirmation, 'Confirmation de mot de passe: ' %><br>
<%= f.password_field :password_confirmation, size: 40 %>
</div>
<div class="field">
<%= f.label :phone, 'Numéro de téléphone: ' %><br>
<%= f.text_field :phone %>
</div>
<div class="actions">
<%= f.submit "Employeur" %>
<%= f.submit "Prestataire" %>
</div>
<% end %>
Employeur form:
<%= form_for [#user, #employeur] do |f| %>
<% if #employeur.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#employeur.errors.count, "error") %> prohibited this employeur from being saved:</h2>
<ul>
<% #employeur.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<div class="field">
<%= f.label :siren, 'Siren: ' %><br>
<%= f.text_field :siren %>
</div>
<div class="field">
<%= f.label :societe, 'Société: ' %><br>
<%= f.text_field :societe %>
</div>
<div class="field">
<%= f.label :code_postal, 'Code Postal: ' %><br>
<%= f.text_field :code_postal %>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
As for my new.html document for employeur:
<h1>New employeur</h1>
<%= render 'form' %>

Answer 1

Here is what's happening:
when you pass <%= form_for [#user, #employeur] do |f| %>, Rails will connect the objects (#user & #employeur) in the order you passed and the then append path to it. So this becomes user_employeurs_path. by convention it will pluralize your the last object (employeur) to infer your controller's name. that's how it gets: user_employeurs_path
so you would either have to pluralize your controller's resources to follow the convention. Or pass url to your path:
<%= form_for [#user, #employeur], url: user_employeur_path do |f| %>

Answer 2

I believe you can use url parameter in this case. Try something like:
<%= form_for [#user, #employeur], url: user_employeur_path do |f| %>
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