Implements #173

Public view for suggested actions as well as resources has been
completelly redesigned.

Private side for this feature has been adapted as well in order to meet
the requirements.

app/models/link.rb

@@ -0,0 +1,7 @@
+class Link < ActiveRecord::Base
+  belongs_to :linkable, polymorphic: true
+
+  validates :label, presence: true
+  validates :url, presence: true
+  validates :linkable, presence: true 
+end