Add search method to polls

So far the method does not take questions nor answers into account.

This way we'll be able to search polls in the SDG Management section.

app/models/poll.rb

@@ -5,6 +5,7 @@ class Poll < ApplicationRecord
   acts_as_paranoid column: :hidden_at
   include ActsAsParanoidAliases
   include Notifiable
+  include Searchable
   include Sluggable
   include StatsVersionable
   include Reportable
@@ -175,4 +176,20 @@ class Poll < ApplicationRecord
   def budget_poll?
     budget.present?
   end
+
+  def searchable_translations_definitions
+    {
+      name        => "A",
+      summary     => "C",
+      description => "D"
+    }
+  end
+
+  def searchable_values
+    searchable_globalized_values
+  end
+
+  def self.search(terms)
+    pg_search(terms)
+  end
 end