Add flash message in rails

In app/helpers/application_helper.rb :-

module ApplicationHelper
    def flash_class(level)
        case level
        when 'notice' then "alert alert-info"
        when 'success' then "alert alert-success"
        when 'error' then "alert alert-error"
        when 'alert' then "alert alert-error"
        end
      end
end

Somewhere in app/views/layouts/application.html.erb:

<%= render 'layouts/flash_messages' %> 

app/views/layouts/_flash_messages.html.erb

<div>
  <% flash.each do |key, value| %>
    <div class="<%= flash_class(key) %> fade in">
      <a href="#" data-dismiss="alert" class="close">×</a>
      <%= value %>
    </div>
  <% end %>
</div>

<style>
.alert {
padding: 8px 35px 8px 14px;
margin-bottom: 18px;
color: #c09853;
text-shadow: 0 1px 0 rgba(255, 255, 255, 0.5);
background-color: #fcf8e3;
border: 1px solid #fbeed5;
-webkit-border-radius: 4px;
-moz-border-radius: 4px;
border-radius: 4px;
}

.alert-heading {
color: inherit;
}

.alert .close {
position: relative;
top: -2px;
right: -21px;
line-height: 18px;
}



.alert-success {
color: #468847;
background-color: #dff0d8;
border-color: #d6e9c6;
}



.alert-danger,
.alert-error {
color: #b94a48;
background-color: #f2dede;
border-color: #eed3d7;
}



.alert-info {
color: #3a87ad;
background-color: #d9edf7;
border-color: #bce8f1;
}

.alert-block {
padding-top: 14px;
padding-bottom: 14px;
}


.alert-block &gt; p,
.alert-block &gt; ul {
margin-bottom: 0;
}

.alert-block p + p {
margin-top: 5px;
}


.alert-success {
color: #468847;
background-color: #dff0d8;
border-color: #d6e9c6;
}

.alert-danger,
.alert-error {
color: #b94a48;
background-color: #f2dede;
border-color: #eed3d7;
}

.alert-info {
color: #3a87ad;
background-color: #d9edf7;
border-color: #bce8f1;
}
</style>