append_to_list_AJAX

projects/index
<h1>Listing projects</h1>

<br />
<div id="projects_list">
  <% @projects.each do |project| %>
    <%= project.name %><br>
  <% end %> 
</div>

<%= link_to 'New Project', new_project_path, id: 'new_link', remote: true %>
=======================================
projects/new.js.erb

$('#new_link').hide().after('<%= j render("form")%>');

=======================================
projects/_form.html.erb

<%= form_for(@project, remote: true) do |f| %>
  <% if @project.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@project.errors.count, "error") %> prohibited this project from being saved:</h2>

      <ul>
      <% @project.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :name %><br />
    <%= f.text_field :name %>
  </div>
  <div class="actions">
    <%= f.submit %>
  </div>
<% end %>

=========================================
projects/create.js.erb

$('#new_project').hide();
$('#new_link').show();
$('#projects_list').append('<%= j render(@project) %>'); // THIS IS WHERE I"M GETTING THE 500 error

==========================
ProjectsController

class ProjectsController < ApplicationController
  # GET /projects
  # GET /projects.json
  def index
    @projects = Project.all

    respond_to do |format|
      format.html # index.html.erb
      format.json { render json: @projects }
    end
  end

  # GET /projects/1
  # GET /projects/1.json
  def show
    @project = Project.find(params[:id])

    respond_to do |format|
      format.html # show.html.erb
      format.json { render json: @project }
    end
  end

  # GET /projects/new
  # GET /projects/new.json
  def new
    @project = Project.new

    respond_to do |format|
      format.html # new.html.erb
      format.json { render json: @project }
      format.js
    end
  end

  # GET /projects/1/edit
  def edit
    @project = Project.find(params[:id])
  end

  # POST /projects
  # POST /projects.json
  def create
    @project = Project.new(params[:project])

    respond_to do |format|
      if @project.save
        format.html { redirect_to @project, notice: 'Project was successfully created.' }
        format.json { render json: @project, status: :created, location: @project }
        format.js
      else
        format.html { render action: "new" }
        format.json { render json: @project.errors, status: :unprocessable_entity }
        format.js
      end
    end
  end

  # PUT /projects/1
  # PUT /projects/1.json
  def update
    @project = Project.find(params[:id])

    respond_to do |format|
      if @project.update_attributes(params[:project])
        format.html { redirect_to @project, notice: 'Project was successfully updated.' }
        format.json { head :no_content }
      else
        format.html { render action: "edit" }
        format.json { render json: @project.errors, status: :unprocessable_entity }
      end
    end
  end

  # DELETE /projects/1
  # DELETE /projects/1.json
  def destroy
    @project = Project.find(params[:id])
    @project.destroy

    respond_to do |format|
      format.html { redirect_to projects_url }
      format.json { head :no_content }
    end
  end
end