add basic logviewer to admin page

app/controllers/admin_controller.rb

 class AdminController < ApplicationController
     before_filter :authenticate, :except => [:login]
     def index
-  end
+          @logs = `tail -n 100 log/minetest.log`
+    end
 end

app/helpers/admin_helper.rb

+module AdminHelper
+end

app/views/admin/index.html.erb

+<% if logged_in? %>
+<h1>Admin</h1>
+<button type="button" class="btn btn-primary pull-right" style="margin-top:-5rem;">Refresh</button>
+<pre id="tail" style="height:600px;"><%= @logs %></pre>
+<% content_for(:after) do %>
+    <script>
+tailScroll();
+
+function updateDiv(){
+$('#tail').triggerevent(function(){
+        $('#tail').html(newContent);
+});
+setInterval(updateDiv, 1000);
+}
+$("button").click(function (e) {
+window.location.reload(true);
+});
+function tailScroll() {
+    var height = $("#tail").get(0).scrollHeight;
+    $("#tail").animate({
+        scrollTop: height
+    }, 500);
+}
+    </script>
+<% end %>
+
+<% else %>
+    <h1> nope </h1>
+<% end %>
+

config/initializers/user.rb

+USER = 'admin'
+PASSWORD = '123'

config/routes.rb

@@ -30,7 +30,6 @@ end
 
 controller :admin do
     get 'admin' => 'admin#index', :as => 'admin'
-    get 'login' => 'admin#login', :as => 'login'
 end
 end