Remove complex methods from follow model. Create instance method followed_by? on followable model concern. Some code improvements.

app/models/concerns/followable.rb

@@ -6,4 +6,8 @@ module Followable
     has_many :followers, through: :follows, source: :user
   end
 
+  def followed_by?(user)
+    followers.include?(user)  
+  end
+
 end

app/models/follow.rb

@@ -6,15 +6,4 @@ class Follow < ActiveRecord::Base
   validates :followable_id, presence: true
   validates :followable_type, presence: true
 
-  scope(:by_user_and_followable, lambda do |user, followable|
-    where(user_id: user.id,
-          followable_type: followable.class.to_s,
-          followable_id: followable.id)
-  end)
-
-  def self.followed?(user, followable)
-    return false unless user
-    !! by_user_and_followable(user, followable).try(:first)
-  end
-
 end