This speeds up gem index updates a lot

Author: Tom Copeland

db/migrate/20091021145813_add_unique_index_to_gem_namespace_ownerships_namespace.rb

@@ -0,0 +1,10 @@
+class AddUniqueIndexToGemNamespaceOwnershipsNamespace < ActiveRecord::Migration
+
+  def self.up
+    add_index :gem_namespace_ownerships, :namespace, :unique => true
+  end
+
+  def self.down
+    remove_index :gem_namespace_ownerships, :namespace
+  end
+end