Feature: Improve label experience (#975)

Co-authored-by: Sojan <sojan@pepalo.com>

db/migrate/20200625124400_migrate_and_add_unique_index_to_labels.rb

@@ -0,0 +1,20 @@
+class MigrateAndAddUniqueIndexToLabels < ActiveRecord::Migration[6.0]
+  def change
+    add_index :labels, [:title, :account_id], unique: true
+    migrate_existing_tags
+  end
+
+  private
+
+  def migrate_existing_tags
+    ::ActsAsTaggableOn::Tag.all.each do |tag|
+      tag.taggings.each do |tagging|
+        ensure_label_for_account(tag.name, tagging.taggable.account)
+      end
+    end
+  end
+
+  def ensure_label_for_account(name, account)
+    account.labels.where(title: name.downcase).first_or_create
+  end
+end