Remove Avatar isn't working for me - ruby-on-rails

Question

The Remove Avatar checkbox isn't doing anything for me on my edit form. Here is my code.
_form.html.erb
<%= simple_form_for(#child, html: { multipart: true}) do |f| %>
<% if child.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(child.errors.count, "error") %> prohibited this child from being saved:</h2>
<ul>
<% child.errors.full_messages.each do |message| %>
<li><%= message %></li>
<% end %>
</ul>
</div>
<% end %>
<%= f.label :name %><br />
<div class="field"><%= f.text_field(:name) %> <br /></div>
<%= f.label :balance %><br />
<div class="field"> <%= f.text_field(:balance) %> <br /></div>
<%= f.label :parent_id %><b> ID</b><br />
<%= f.number_field :parent_id, :value => current_parent.id, :readonly => true %><br />
<%=f.label :avatar %><br />
<%= image_tag(#child.avatar_url) if #child.avatar? %>
<%= f.file_field(:avatar) %>
<%= f.hidden_field(:avatar_cache) %>
<br />
<label>
<%= f.check_box :remove_avatar %>
Remove Avatar
</label>
<div class="actions">
<% if #child.new_record? == true %>
<%= f.submit("Add Child") %>
<% else %>
<%= f.submit("Save Child") %>
<% end %>
</div>
<% end %>
Child Controller
class ChildrenController < ApplicationController
before_filter :authenticate_parent!
before_action :set_child, only: [:show, :edit, :update, :destroy]
# GET /children
# GET /children.json
def index
#children = Child.all
end
# GET /children/1
# GET /children/1.json
def show
end
# GET /children/new
def new
#child = Child.new
end
# GET /children/1/edit
def edit
end
# POST /children
# POST /children.json
def create
#child = Child.new(child_params)
if #child.avatar.file.nil?
img = LetterAvatar.generate(#child.name, 200)
File.open(img) do |f|
#child.avatar = f
end
end
respond_to do |format|
if #child.save
format.html { redirect_to #child, notice: 'Child was successfully created.' }
format.json { render :show, status: :created, location: #child }
else
format.html { render :new }
format.json { render json: #child.errors, status: :unprocessable_entity }
end
end
end
# PATCH/PUT /children/1
# PATCH/PUT /children/1.json
def update
if #child.avatar.file.nil?
img = LetterAvatar.generate(#child.name, 200)
File.open(img) do |f|
#child.avatar = f
end
end
respond_to do |format|
if #child.update(child_params)
format.html { redirect_to #child, notice: 'Child was successfully updated.' }
format.json { render :show, status: :ok, location: #child }
else
format.html { render :edit }
format.json { render json: #child.errors, status: :unprocessable_entity }
end
end
end
# DELETE /children/1
# DELETE /children/1.json
def destroy
#child.destroy
respond_to do |format|
format.html { redirect_to children_url, notice: 'Child was successfully destroyed.' }
format.json { head :no_content }
end
end
private
# Use callbacks to share common setup or constraints between actions.
def set_child
#child = Child.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def child_params
params.fetch(:child, {}).permit(:name, :balance, :parent_id, :avatar)
# params.fetch(:user, {}).permit(:first_name, :last_name, :email, :phone,
end
end
If I click save with the Remove Avatar box checked, it literally does nothing to the avatar, if I go back to any page that displayed the avatar, it is still there. What am I doing wrong? I am using Ruby on Rails 5.0.1
Side note: I am aware of some of the deprecated things that are being used here, such as before_filter. I am working with a large group of people so not all of this code is mine, fixing it is not priority at the moment.