Error in RoR: undefined method '[]' for nil: NilClass - NoMethodError in Site :: Home # index

This application was made using the following Bootstrap template: link

In my case, after I made all the changes and adaptations, correctly doing the ASSETS and PRE-COMPILE'S, the application ran perfectly on my machine (locally / development).

When placing the application on heroku, the application does not work by apprehending the following errors (carousel errors):

  

NoMethodError in Site :: Home # index Showing   /app/app/views/site/home/_content1.html.erb where line # 16 raised:

     

undefined method '[]' for nil: NilClass Extracted source (around line # 16):

<div class="container">
    <div class="row">
        <div class="box" style="background-color: #E98317;">
            <div class="col-lg-12 text-center">
                <div id="carousel-example-generic" class="carousel slide">
                    <!-- Indicators -->
                    <ol class="carousel-indicators hidden-xs">
                        <li data-target="#carousel-example-generic" data-slide-to="0" class="active"></li>
                        <li data-target="#carousel-example-generic" data-slide-to="1"></li>
                        <li data-target="#carousel-example-generic" data-slide-to="2"></li>
                    </ol>

                    <!-- Wrapper for slides -->
                    <div class="carousel-inner">
                        <div class="item active" style="height: 600px;">
                            <%= image_tag "img/slide-5.jpg", :class => "img-responsive" %>
                        </div>
                        <div class="item" style="height: 600px;">
                            <%= image_tag "img/slide-4.jpg", :class => "img-responsive" %>
                        </div>
                        <div class="item" style="height: 600px;">
                            <%= image_tag "img/slide-3.jpg", :class => "img-responsive" %>
                        </div>
                    </div>

                    <!-- Controls -->
                    <a class="left carousel-control" href="#carousel-example-generic" data-slide="prev">
                        <span class="icon-prev"></span>
                    </a>
                    <a class="right carousel-control" href="#carousel-example-generic" data-slide="next">
                        <span class="icon-next"></span>
                    </a>
                </div>
                <div class="box" style="background-color: white;">
                    <h2 class="brand-before">
                        <small>Bem vindo(a) à página da</small>
                    </h2>
                    <h1 class="brand-name">Superar Cursos</h1>
                    <hr class="tagline-divider">
                    <h2>
                        <small>Centro
                            <strong>Profissionalizante</strong>
                        </small>
                    </h2>
                </div>
            </div>
        </div>
    </div>


</div>


<!-- Script to Activate the Carousel -->
<script>

$('.carousel').carousel({
interval: 5000 //changes the speed
})
</script>