migration to fix video_embed_url in existing projects (the new url will always contain the // before the host

db/migrate/20140605174230_fix_vide_embed_urls.rb

@@ -0,0 +1,7 @@
+class FixVideEmbedUrls < ActiveRecord::Migration
+  def change
+    execute "
+    UPDATE projects SET video_embed_url = regexp_replace(video_embed_url, '^(\\w)', '//\\1');
+    "
+  end
+end