Tweak SQL migration for PostgreSQL [spree#1273]

core/db/migrate/20120315064358_migrate_images_from_products_to_variants.rb

@@ -1,36 +1,34 @@
 class MigrateImagesFromProductsToVariants < ActiveRecord::Migration
   def up
-    images = select_all('SELECT spree_assets.* FROM spree_assets
-                         WHERE spree_assets.type IN ("Spree::Image")
-                         AND spree_assets.viewable_type = "Spree::Product"')
+    images = select_all("SELECT spree_assets.* FROM spree_assets
+                         WHERE spree_assets.type IN ('Spree::Image')
+                         AND spree_assets.viewable_type = 'Spree::Product'")
 
     images.each do |image|
       master_variant_id = select_value("SELECT id FROM spree_variants
                                         WHERE product_id = #{image['viewable_id']}
                                         AND is_master = 't'")
 
-      execute("UPDATE spree_assets SET viewable_type = 'Spree::Variant',
-               viewable_id = #{master_variant_id}
+      execute("UPDATE spree_assets SET viewable_type = 'Spree::Variant', viewable_id = #{master_variant_id}
                WHERE id = #{image['id']}") if master_variant_id
     end
   end
 
   def down
-    images = select_all('SELECT spree_assets.* FROM spree_assets
-                            JOIN spree_variants
-                            ON spree_variants.id = spree_assets.viewable_id
-                            AND spree_variants.is_master = "t"
-                            WHERE spree_assets.type IN ("Spree::Image")
-                            AND spree_assets.viewable_type = "Spree::Variant"')
+    images = select_all("SELECT spree_assets.* FROM spree_assets
+                         JOIN spree_variants
+                         ON spree_variants.id = spree_assets.viewable_id
+                         AND spree_variants.is_master = 't'
+                         WHERE spree_assets.type IN ('Spree::Image')
+                         AND spree_assets.viewable_type = 'Spree::Variant'")
 
     images.each do |image|
       product_id = select_value("SELECT spree_products.id FROM spree_products
                                  JOIN spree_variants
                                  ON spree_variants.id = #{image['viewable_id']}
                                  AND spree_products.id = spree_variants.product_id")
 
-      execute("UPDATE spree_assets SET viewable_type = 'Spree::Product',
-               viewable_id = #{product_id}
+      execute("UPDATE spree_assets SET viewable_type = 'Spree::Product', viewable_id = #{product_id}
                WHERE id = #{image['id']}") if product_id
     end
   end