rails 4 unpermitted params nested form - ruby-on-rails

Question

I know there are alot of these kinds of posts on SO, and I think Ive read and tried each of them, all without success.
I have Post and Image models that I need to work together with a many to one relationship.
class Post < ActiveRecord::Base
has_many :images
end
class Image < ActiveRecord::Base
belongs_to :post
mount_uploader :file, images_uploader
end
Here is the post_parms declaration in my posts controller, which includes all of the fields in my image model migration.
private
def post_params
params.require(:post).permit(:title, :content, image_attributes: [:id, :post_id, :file])
end
and here is my post creation form where, I hope to allow multiple image asset creation with each post.
<%= form_for #post, html: {class: "pure-form pure-form-stacked"} do |post| %>
<%= post.fields_for :image, :html => { :multipart => true } do |image| %>
<%= image.label :file, "Upload Image:" %>
<%= image.file_field :file, multiple: true %>
<% end %>
<fieldset class="post-form">
<%= post.label :title %>
<%= post.text_field :title %>
<%= post.label :content %>
<%= post.text_area :content, :class => "redactor", :rows => 40, :cols => 120 %>
</fieldset>
<div class = "button-box">
<%= post.submit class: "pure-button pure-button-primary" %>
<%= link_to "Cancel", posts_path, :class => "pure-button" %>
</div>
Despite repeated effort and reading every post I can find on this topic, I'm still getting:
Unpermitted parameters: image
The trouble here is that this error provides no clue where to start looking for the problem. Since Im not really sure where to look next I thought I would post it here looking for more professional opinions.

Answer 1

Update the Post model as below:
class Post < ActiveRecord::Base
has_many :images
accepts_nested_attributes_for :images ## Add this
end
This way upon form submission you would receive the image attributes in key images_attributes and not image which you are currently receiving which is causing the warning as Unpermitted parameters: image
As you have 1-M relationship between Post and Image
You need to update post_params as below:
def post_params
params.require(:post).permit(:title, :content, images_attributes: [:id, :post_id, :file])
end
Use images_attributes (Notice plural images) and NOT image_attributes (Notice singular image)
And change fields_for in your view as
<%= post.fields_for :images, :html => { :multipart => true } do |image| %>
Use images (Notice plural) and NOT image (Notice singular)
UPDATE
To resolve uninitialized constant Post::Image error
Update Image model as below:
class Image < ActiveRecord::Base
belongs_to :post
## Updated mount_uploader
mount_uploader :file, ImagesUploader, :mount_on => :file
end
Also, suggested to remove multiple: :true from
<%= ff.file_field :file, multiple: true %>