Blank screen when clicking on Follow button

 class UserFriendshipsController < ApplicationController
   before_filter :authenticate_user!

   def index
     @user_friendships != @user_friendships
   end

   def accept
      @user_friendship = current_user.user_friendships.find(params [:id])
      if @user_friendship.accept!
       flash[:success] = "You are now friends with #   {@user_friendship.friend.name}"
      else
       flash[:error] = "That friendship could not be accepted"
      redirect_to user_friendships_path
   end

   def new
     if params[:friend_id]
       @friend = User.find(params[:friend_id])
       raise ActiveRecord::RecordNotFound if @friend.nil?
       @user_friendship = current_user.user_friendships.new(friend: @friend)
     else
       flash[:error] = "Friend required"
     end
   rescue ActiveRecord::RecordNotFound
     render file: 'public/404', status: :not_found
   end

   def create
     if params[:user_friendship] && params[:user_friendship].has_key?(:friend_id)
       @friend = User.find(params[:user_friendship][:friend_id])
       @user_friendship = current_user.user_friendships.new(friend: @friend)
       if @user_friendship.save
         flash[:success] = "You are now friends!"
       else
         flash[:error] = "There was a problem."
       end
       redirect_to user_path(@friend)
     else
       flash[:error] = "Friend required"
       redirect_to root_path
     end
   end

  def edit
  end

 end
 end

   <% @user_Friendships.each do |friendship| %>
        <% friend = friendship.friend %>
            <div id="<%= dom_id(friendship) %>" class="friend row">
         <div class="span1">
        <center><%= link_to image_tag(user.avatar.url(:thumb)), user %></center>
         </div>
         <div class="span7">
            <strong><%= friend.name %></strong><br />
            <%if friendship.pending? %>
            <em>Frienship is pending.</em> <%=link_to "Delete request", edit_user_friendship_path(friendship) %>.
            <% end %>
            <% if friendship.requested? %>
                <em>Friendship requested.</em> <%= link_to "Accept Friendship", edit_user_friendship_path(friendship) %>.
            <% end %>
            <% if friendship.accepted? %>
                     <em>Friendship started <%= friendship.updated_at %>.</em> <%= link_to "Update friendship", edit_user_friendship_path(friendship) %>.
            <% end %>
             </div>
         </div>
     <% end %>

          <% if @friend %>
          <h1><%= @friend.name %></h1>

     <p> Would you like to add <%= @friend.name %>?</p>

     <%= form_for @user_friendships, method: :post do |form| %>
    <div class="form form-actions">
        <%= form.hidden_field :friend_id, value: @friend %>
        <%= submit_tag "Yes, Add Friend", class: 'btn btn-primary' %>
        <%= link_to "Cancel", current_user, class: 'btn btn-default' %>
    </div>  
    <% end %>

    <% end %>