artists: rename is_active flag to is_deleted.

Rename is_active to is_deleted. This is for better consistency with
other models, and to reduce confusion over what "active" means for
artists. Sometimes users think active is for whether the artist is
actively producing work.

db/migrate/20200306202253_rename_is_active_on_artists.rb

@@ -0,0 +1,25 @@
+class RenameIsActiveOnArtists < ActiveRecord::Migration[6.0]
+  def up
+    execute "SET statement_timeout = 0"
+
+    rename_column :artists, :is_active, :is_deleted
+    change_column_default :artists, :is_deleted, from: true, to: false
+    execute "UPDATE artists SET is_deleted = NOT is_deleted"
+
+    rename_column :artist_versions, :is_active, :is_deleted
+    change_column_default :artist_versions, :is_deleted, from: true, to: false
+    execute "UPDATE artist_versions SET is_deleted = NOT is_deleted"
+  end
+
+  def down
+    execute "SET statement_timeout = 0"
+
+    execute "UPDATE artists SET is_deleted = NOT is_deleted"
+    change_column_default :artists, :is_deleted, from: false, to: true
+    rename_column :artists, :is_deleted, :is_active
+
+    execute "UPDATE artist_versions SET is_deleted = NOT is_deleted"
+    change_column_default :artist_versions, :is_deleted, from: false, to: true
+    rename_column :artist_versions, :is_deleted, :is_active
+  end
+end