Simplify LEFT JOIN using ActiveRecord#left_joins

This method is available since Rails 5.0.

app/models/poll.rb

@@ -99,8 +99,8 @@ class Poll < ApplicationRecord
   def self.answerable_by(user)
     return none if user.nil? || user.unverified?
 
-    current.joins('LEFT JOIN "geozones_polls" ON "geozones_polls"."poll_id" = "polls"."id"')
-           .where("geozone_restricted = ? OR geozones_polls.geozone_id = ?", false, user.geozone_id)
+    current.left_joins(:geozones)
+      .where("geozone_restricted = ? OR geozones.id = ?", false, user.geozone_id)
   end
 
   def self.votable_by(user)