First argument in form cannot contain nil - ruby-on-rails

Question

I tried to use Ajax request for creating a new object and this had been working very well. In my view file I used to set remote: true option for link_to and everything was fine.
Now I want to render my _form partial once the view file is loaded without a link, but just using a <%= render 'form' %>.
I don't understand why I am getting this error. Who can enlighten me what am I doing wrong?
views/tasks/index.html
<h3>Tasks database</h3>
<table>
<% #tasks.each do |task| %>
<tr class='tasks' id="task_<%= task.id %>">
<td>
<%= link_to user_task_path(current_user, task.id), method: :delete,
data: { confirm: 'Are you sure?' }, remote: true do %>
<i class="glyphicon glyphicon-trash"></i>
<% end %>
<a href="#" data-xeditable="true" data-pk="task" data-model='task' data-name='title'
data-url="/users/<%= current_user.id %>/tasks/<%= task.id %>" data-title="Enter title">
<i><%= task.title %></i>
</a>
</td>
</tr>
<% end %>
<tr>
<td><%= render 'form' %></td>
</tr>
</table>
controllers/tasks_controller.rb
class TasksController < ApplicationController
before_filter :authorize, only: [:edit, :new, :destroy]
def index
#tasks = current_user.tasks
end
def show
#task = Task.find(params[:id])
redirect_to users_path
end
def edit
#task = Task.find(params[:id])
end
def new
#task = Task.new
end
def create
#task = current_user.tasks.new(task_params)
respond_to do |format|
if #task.save
format.html { redirect_to user_tasks_path(current_user) }
format.js
else
format.html { render action: 'new' }
format.js
end
end
end
def update
#task = Task.find(params[:id])
respond_to do |format|
if #task.update(task_params)
format.html { redirect_to user_tasks_path(current_user), notice: 'Post successfully was updated.'}
format.json { head :no_content }
else
format.html { render action: 'edit' }
format.json { head :no_content }
end
end
end
def destroy
#task = Task.find(params[:id])
#task.destroy
respond_to {|format| format.js }
end
private
def task_params
params.require(:task).permit(:title)
end
end
views/tasks/_form.html
<%= form_for [current_user, #task], remote: true do |f| %>
<%= f.text_field :title %>
<%= f.hidden_field :user_id, value: params[:user_id] %>
<%= f.submit %>
<% end %>
views/tasks/create.js
$('#new_task').remove();
$('#new_link').show();
$('.tasks').last().after("<%=j render partial: 'task', :locals => { :task => #task } %>");
setXeditable();
Here is my rake routes
Any help?

Answer 1

First argument in form cannot contain nil or be empty
You are rendering form in index page and you didn't set #task in index method.
You should set #task in index method
def index
#tasks = current_user.tasks
#task = Task.new
end