DEV: Change upload verified column to be integer (#10643)

Per review https://review.discourse.org/t/dev-add-verified-to-uploads-and-fill-in-s3-inventory-10406/14180

Change the verified column for Upload to a verified_status integer column, to avoid having NULL as a weird implicit status.

db/migrate/20200910051633_change_uploads_verified_to_integer.rb

@@ -0,0 +1,21 @@
+# frozen_string_literal: true
+
+class ChangeUploadsVerifiedToInteger < ActiveRecord::Migration[6.0]
+  def up
+    add_column :uploads, :verification_status, :integer, null: false, default: 1
+    Migration::ColumnDropper.mark_readonly(:uploads, :verified)
+
+    DB.exec(
+      <<~SQL
+      UPDATE uploads SET verification_status = CASE WHEN
+        verified THEN 2
+        WHEN NOT verified THEN 3
+        END
+      SQL
+    )
+  end
+
+  def down
+    remove_column :uploads, :verification_status
+  end
+end

db/migrate/20200911031738_add_index_to_uploads_verification_status.rb

@@ -0,0 +1,16 @@
+# frozen_string_literal: true
+
+class AddIndexToUploadsVerificationStatus < ActiveRecord::Migration[6.0]
+  disable_ddl_transaction!
+
+  def up
+    execute <<~SQL
+      CREATE INDEX CONCURRENTLY IF NOT EXISTS
+      idx_uploads_on_verification_status ON uploads USING btree (verification_status)
+    SQL
+  end
+
+  def down
+    execute "DROP INDEX IF EXISTS idx_uploads_on_verification_status"
+  end
+end