Error on migration from 0.6.2 - column "default_branch" contains null values

[sam002]

updating from 0.6.2 to 0.7 with postgresql after "RAILS_ENV=production rake redmine:plugins:migrate":

Migrating redmine_git_hosting (Redmine Git Hosting Plugin)...
==  AddDefaultBranchToRepositoryGitExtra: migrating ===========================
-- add_column(:repository_git_extras, :default_branch, :string, {:null=>false, :after=>:git_notify})
rake aborted!
An error has occurred, this and all later migrations canceled:

PGError: ERROR:  column "default_branch" contains null values
: ALTER TABLE "repository_git_extras" ADD COLUMN "default_branch" character varying(255) NOT NULL/home/redmine/redmine/plugins/redmine_git_hosting/db/migrate/20140305083200_add_default_branch_to_repository_git_extra.rb:4:in `up'

My hotfix:

diff --git a/db/migrate/20140305083200_add_default_branch_to_repository_git_extra.rb b/db/migrate/20140305083200_add_default_branch_to_repository_git_extra.rb
index de7c713..1e2d42f 100644
--- a/db/migrate/20140305083200_add_default_branch_to_repository_git_extra.rb
+++ b/db/migrate/20140305083200_add_default_branch_to_repository_git_extra.rb
@@ -1,7 +1,7 @@
 class AddDefaultBranchToRepositoryGitExtra < ActiveRecord::Migration

   def self.up
-    add_column :repository_git_extras, :default_branch, :string, :null => false, :after => :git_notify
+    add_column :repository_git_extras, :default_branch, :string, :null => false, :default=>"master", :after => :git_notify
   end

   def self.down

How correctly to fix it?