Add migration to remove commas from prior weight notes

db/schema.rb

@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180529093006) do
+ActiveRecord::Schema.define(version: 20180530201303) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"

ee/db/migrate/20180530201303_remove_commas_from_weight_note.rb

+# See http://doc.gitlab.com/ce/development/migration_style_guide.html
+# for more information on how to write migrations for GitLab.
+
+class RemoveCommasFromWeightNote < ActiveRecord::Migration
+  include Gitlab::Database::MigrationHelpers
+  DOWNTIME = false
+
+  def up
+    ActiveRecord::Base.connection.execute(<<-EOQ)
+      UPDATE notes
+      SET notes.note = SUBSTRING(notes.note, 1, LEN(notes.note) - 1)
+      FROM system_note_metadata 
+      WHERE system_note_metadata.note_id = notes.id AND notes.system AND system_note_metadata.action = 'weight' AND notes.note LIKE '%,'
+    EOQ
+  end
+
+  def down
+    old_notes = Note.where("note LIKE 'changed weight to%'")
+
+    old_notes.find_each do |note|
+      note.update_column(:note, note.note.concat(','))
+    end
+  end
+end

ee/spec/migrations/remove_commas_from_weight_note_spec.rb

+require 'spec_helper'
+require Rails.root.join('ee', 'db', 'migrate', '../../db/migrate/20180530201303_remove_commas_from_weight_note.rb')
+
+describe RemoveCommasFromWeightNote, :migration do
+  let(:migration) { described_class.new }
+
+  describe '#up' do
+    let(:notes) {table(:notes)}
+
+    let!(:note_1) {notes.create(note: 'changed weight to 5,')}
+    let!(:note_2) {notes.create(note: 'removed the weight')}
+
+    it 'removes all trailing commas' do
+      expect { migrate! }.to change { Note.where("note LIKE '%,'").count }.from(1).to(0)
+    end
+  end
+
+  describe '#down' do
+    let(:notes) {table(:notes)}
+
+    let!(:note_1) {notes.create(note: 'changed weight to 5')}
+    let!(:note_2) {notes.create(note: 'removed the weight')}
+
+    it 'adds trailing commas' do
+      expect { migration.down }.to change { Note.where("note LIKE '%,'").count }.from(0).to(1)
+    end
+  end
+end