Can't get a custom edit form to save - ruby-on-rails

Question

I want to have a form to just edit one field for my user's model that is separate from the scaffold generated _form.erb.
The form will show but it will not save. When I modify the def in the controller with a respond_to block, the form is bypassed and I just get the record shown.
employee_supervisor_edit.html.erb has <%= render 'employee_supervisor_form' %>
routes.rb contains match '/employee_supervisor_edit/:id' => 'users#employee_supervisor_edit' , via: [:get, :post ]
the form is _employee_supervisor_form.erb
users_controller.rb has
def employee_supervisor_edit
#users = User.all
#user = User.find(params[:id])
respond_to do |format|
if #user.update(user_params)
format.html { redirect_to #user, notice: 'User was successfully updated.' }
format.json { render :show, status: :ok, location: #user }
else
format.html { render :edit }
format.json { render json: #user.errors, status: :unprocessable_entity }
end
end
end
I also have have the following in my users controller.
def user_params
# params.require(:user).permit(:login,
params.permit(:login,
:group_strings,
:name,
:ou_strings,
:email,
:active_employee,
:last_name,
:first_name,
:is_supervisor,
:#supervisor_id)
end
end
If I comment out the whole respond_to block, the form appears but no data is saved. If I put the respond_to block in, then the form is bypassed and it goes right to the show method.
I'm not sure if the problem is related to getting the following error if I use params.require(:user).permit(:login, instead of params.permit(:login,
ActionController::ParameterMissing in UsersController#employee_supervisor_edit
param is missing or the value is empty: user
Rails.root: C:/Users/cmendla/RubymineProjects/employee_observations
Application Trace | Framework Trace | Full Trace
app/controllers/users_controller.rb:134:in `user_params'
app/controllers/users_controller.rb:16:in `block in employee_supervisor_edit'
app/controllers/users_controller.rb:15:in `employee_supervisor_edit'
========== added ==============
I have the following associations in my user.rb
Class User < ActiveRecord::Base
has_many :subordinates, class_name: "User", foreign_key: "supervisor_id"
belongs_to :supervisor, class_name: "User"
======== added : =====================
<%= 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 |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
User Login: <%= #user.login %><br>
User Name: <%= #user.name %> <br>
<div class="field">
<%= f.label :active_employee %>
<%= f.check_box :active_employee %>
</div>
<div class="field">
<%= f.label :supervisor %>
<%= f.collection_select(:supervisor_id, User.order('name'), :id, :name, prompt: true)%>
</div>
<div class="actions">
<%= f.submit %>
</div>
<% end %>

Answer 1

The problem stemmed from my data. Since I am in the development process, I don't have all the error checking I need in place. Null fields or associations pointing to non existent records cause errors where it isn't always obvious (at least to me) that the problem is the data, not the code itself.
I went in with an sql editor and made sure that the contents causing the issues were not set to null and that the columns such as supervisor_id were pointing to actual existing records, not records that were deleted.
I changed params.permit(:login, back to params.require(:user).permit(:login, and now the form is saving as expected.
My next step will be to add validations for input and some error checking for the index and show methods. For the long term, I think that I need to become more proficient with testing as that might show areas that could cause these types of issues.