Approve or Reject Followers using the Relationship Model from RailsTutorial.org
private

    # Return an SQL condition for users followed by the given user.
    # We include the user's own id as well.
    def self.followed_by(user)
        following_ids = %(SELECT followed_id FROM relationships
                    WHERE follower_id = :user_id AND status = "approved")
        where("user_id IN (#{following_ids}) OR user_id = :user_id",
                    { :user_id => user })
end

<table summary="Information about following/followers">
  <tr>
    <td class="main">
      <% unless @users.empty? %>
        <ul class="users">
        <% @users.each do |user| %>
        <tr>
            <td><%= image_tag user.avatar.url(:thumb) %></td>
            <td><%= user.full_name %></td>
            <td><%= user.company %></td>
            <td><%= render 'decide_form' if signed_in? %></td>
        </tr>
        <% end %>
        </ul>
        <%= will_paginate @users %>
      <% end %>
    </td>
  </tr>
</table>

<div id="follow_form">
  <% if @user.following?(current_user) %>
    <%= render 'reject' %>
  <% else %>
    <tr><%= render 'accept' %></tr>
    <tr><%= render 'reject' %></tr>
  <% end %>

<%= form_for current_user.relationships.find_by_followed_id(@user),
         :html => { :method => :delete } do |f| %>
  <div class="actions"><%= f.submit "Unfollow" %></div>
<% end %>