migrate project watchers_count

db/migrate/20200518092612_change_project_watchers_count.rb

@@ -0,0 +1,12 @@
+class ChangeProjectWatchersCount < ActiveRecord::Migration[5.2]
+  def change
+    watcher_ids = Watcher.where(watchable_type: "Project").pluck(:watchable_id).uniq 
+    watcher_ids.each do |i|
+      puts "#######____update_project_watchers_id____##############{i}"
+      p = Project.includes(:watchers).select(:id, :watchers_count).find_by(i) 
+      if p.present?
+        p.update_attribute(:watchers_count, p.watchers.size)
+      end
+    end
+  end
+end