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db/migrate/20190705011739_add_praises_count_for_challenges.rb

@@ -0,0 +1,12 @@
+class AddPraisesCountForChallenges < ActiveRecord::Migration[5.2]
+  def change
+    add_column :challenges, :praises_count, :integer, :default => 0
+
+    challenges = Challenge.where(nil)
+    challenges.each do |c|
+      praises_count = c.praise_tread.where(praise_or_tread: 1).count
+      c.update_column(:praises_count, praises_count)
+    end
+
+  end
+end