Defining local variables within partial templates using AJAX / Ruby on Rails

I have a deeply nested partial view, where I iterate over a collection of @users. The controller defines the @users like so:

class UsersController < ApplicationController

def following
  @users = @user.followed_users
  ..
end

In the partial templates, I iterate over the collection, but I never define the individual of a collection as an instance variable, instead I pass the local variables along with :object:

<% if current_user.following?(user) %>
  <%= render partial: 'unfollow', object: user, as: :user %>
<% else %>
  <%= render partial: 'follow', object: user, as: :user %>
<% end %>

Problem is...

Inside the create.js.erb file that handles the Follow action, for example, I use the following code:

$('#follow_form').html("<%=j render partial: 'users/unfollow', object: user, as: :user %>");

This gives me the following errors from my dev log:

ActionView::Template::Error (undefined local variable or method `user' for #<#:0x007fa17b9e57e0>):

Am I declaring the partial wrong in jQuery? Do I have to define user somewhere else, like in the controller? If so how do I define an individual of a collection as an instance variable?

Thanks in advance!

EDIT: Included associated controller

Here is the associated controller that handles the request:

class RelationshipsController < ApplicationController

def create
debugger
@user = User.find(params[:relationship][:followed_id])
current_user.follow!(@user)
respond_to do |format|
  format.html { redirect_to @user }
  format.js
end
end