add viewer to user_creations

db/migrate/20160926140426_add_viewer_to_user_creations.rb

@@ -0,0 +1,13 @@
+Sequel.migration do
+  up do
+    alter_table :user_creations do
+      add_column :viewer, :boolean, null: false, default: false
+    end
+  end
+
+  down do
+    alter_table :user_creations do
+      drop_column :viewer
+    end
+  end
+end