Refactor: Add and use helpers for links to official pages

Author: yasulab

app/helpers/application_helper.rb

@@ -85,26 +85,18 @@ def news_path(options={anchor: 'news'})
     root_path(options)
   end
 
-  def news_url(path='/')
-    'https://news.coderdojo.jp' + path
-  end
-
-  def decadojo_url; 'https://decadojo.coderdojo.jp'; end
-  def dojocon_url;  'https://dojocon.coderdojo.jp';  end
+  def news_url(path='/'); 'https://news.coderdojo.jp' + path; end
+  def dojomap_url(path='/'); 'https://map.coderdojo.jp' + path; end
+  def zen_url(path='/find'); 'https://zen.coderdojo.com' + path; end
 
-  def dojoletter_url()
-    'https://news.coderdojo.jp/category/DojoLetterバックナンバー'
-  end
+  def decadojo_url;   'https://decadojo.coderdojo.jp'; end
+  def dojocon_url;    'https://dojocon.coderdojo.jp';  end
+  def dojoletter_url; 'https://news.coderdojo.jp/category/DojoLetterバックナンバー'; end
+  def foundation_url; 'https://speakerdeck.com/helloworldfoundation'; end
 
-  def dojomap_url(path='/')
-    'https://map.coderdojo.jp' + path
-  end
+  def facebook_group_url; 'https://www.facebook.com/groups/coderdojo.jp'; end
+  def facebook_page_url;  'https://www.facebook.com/coderdojo.jp'; end
+  def twitter_url;        'https://twitter.com/CoderDojoJapan'; end
+  def youtube_url;        'https://youtube.com/CoderDojoJapan'; end
 
-  def foundation_url
-    'https://speakerdeck.com/helloworldfoundation'
-  end
-
-  def zen_url(path='/find')
-    'https://zen.coderdojo.com' + path
-  end
 end

app/views/shared/_footer.html.erb

@@ -19,13 +19,13 @@
     <%= link_to news_url do %>
       <i class="fa fa-newspaper-o fa-3x fa-fw" aria-hidden="true" title="News"></i>
     <% end %>
-    <%= link_to "https://www.facebook.com/coderdojo.jp/" do %>
+    <%= link_to facebook_page_url do %>
       <i class="fa fa-facebook fa-3x fa-fw" aria-hidden="true" title="Facebook"></i>
     <% end %>
-    <%= link_to "https://twitter.com/CoderDojoJapan" do %>
+    <%= link_to twitter_url do %>
       <i class="fa fa-twitter fa-3x fa-fw" aria-hidden="true" title="Twitter"></i>
     <% end %>
-    <%= link_to "https://www.youtube.com/CoderDojoJapan" do %>
+    <%= link_to youtube_url do %>
       <i class="fa fa-youtube fa-3x fa-fw" aria-hidden="true" title="YouTube"></i>
     <% end %>
     <%= link_to podcasts_path do %>