Optionally touch all ancestors on save (see ActiveRecord#belongs_to)
Update .travis.yml to use rbx not rbx-19mode

See https://github.com/travis-ci/travis-ci/issues/1641
add rubysl to the gem file for rbx/rvm travis-ci issue

Conflicts:
	Gemfile
Merge pull request #224 from rathgar/2-1-stable

Optionally touch all ancestors on save
Fixed scope_for_rebuild, NULL values cannot be compared with SQL = operator.
Removed rbx-18mode as it doesn't exist.
2-1-stable: fix deleting a parent may lead to a stale object error

Redmine Defect 7920
Attempted to update a stale object when copying a project
http://www.redmine.org/issues/7920

This revision passes Redmine test.
http://www.redmine.org/projects/redmine/repository/entry/trunk/test/unit/issue_nested_set_test.rb?rev=12679#L244

https://travis-ci.org/marutosi/redmine/jobs/17215987#L1979

<pre>
  1) Error:
test_destroy_parent_issue_updated_during_children_destroy(IssueNestedSetTest):
ActiveRecord::StaleObjectError: Attempted to destroy a stale object: Issue
    app/models/issue.rb:179:in `destroy'
    test/unit/issue_nested_set_test.rb:250:in `test_destroy_parent_issue_updated_during_children_destroy'
    test/unit/issue_nested_set_test.rb:249:in `test_destroy_parent_issue_updated_during_children_destroy'
</pre>
2-1-stable: fix ActiveRecord::StatementInvalid: Error: Column 'lft' in order clause is ambiguous

On 2-1-stable 3d5ac746542, Redmine test fails.
https://bitbucket.org/marutosi/redmine-bb-awesome_nested_set-use-gem/src/2ac1078370/Gemfile#cl-10
https://drone.io/bitbucket.org/marutosi/redmine-bb-awesome_nested_set-use-gem/2

<pre>
 13) Error:
    test_visible_and_nested_set_scopes(IssueTest):
    ActiveRecord::StatementInvalid: Mysql2::Error: Column 'lft' in order clause is ambiguous:
</pre>

http://www.redmine.org/projects/redmine/repository/revisions/12689/annotate/trunk/test/unit/issue_test.rb#L332
<pre>
  def test_visible_and_nested_set_scopes
    assert_equal 0, Issue.find(1).descendants.visible.all.size
  end
</pre>
Fix for mssql with jruby/activerecord-jdbc-adapter

Fix for the following error with mssql with jruby/activerecord-jdbc-adapter:
ActiveRecord::StatementInvalid: ActiveRecord::JDBCError: No column was specified for column 3 of 't'.: SELECT t.* FROM ( SELECT ROW_NUMBER() OVER(ORDER BY MIN(users.id)) AS _row_num, [users].[lft], COUNT([users].[lft]) FROM [users]  GROUP BY [users].[lft] HAVING COUNT([users].[lft]) > 1 ) AS t WHERE t._row_num BETWEEN 1 AND 1
Allow use of non-id primary column

Closes #239.
Add specs, fixtures, and model for non-standard primary keys
Don't rework how scope works
Add parallel specs for categories and users [broken]

I don't know why these are broken. Is it because we're using
fixtures? I don't know.

Pretty much all of the specs that are broken for
models/users are also broken in models/categories,
so I expect this is an issue with the testing environment
rather than an issue with the actual code.
Ensure UUID on Users models
Remove duplicate categories_spec
Fix rebuild! to use parent_id instead of id
Change to 'new_parent_id' to be more accurately named
Keep order for rebuild the same (use model primary key)
Order by specified primary key column when validating duplicates
Merge pull request #241 from shekibobo/named-primary-key

Allow use of non-id primary column