Test all supported Rails versions on Travis CI
Merge pull request #12 from felixbuenemann/rails-version-ci-testing

Test all supported Rails versions on Travis CI
1.3.0 release prep.
adds root? method
adds leaf? method
Merge pull request #13 from xuanxu/extra_methods

Adds node.root? and node.leaf? methods.
add a class method "tree_view" to show records in a tree view
move tree_view into ExtendClassMethods module
add test for tree_view method
Test against Rails 4.0 final on Travis CI
move tree_view method into ActsAsTree::Presentation and let the user mix it into his classes as required
Merge pull request #14 from rainchen/add_tree_view

add a class method "tree_view" to show records in a tree view
1.4.0 release prep.
Added descendants methods

This resolves #15.
fix warning

warning: assigned but unused variable - order_option
Merge pull request #16 from akicho8/patch-1

remove unused var order_option
1.5.0 Release Prep
Adding note about becoming a committer. 

For many months now I've been giving every contributor that we've accepted a patch from push access to the project. Adding a note about that to the Pull Request part of the README seemed long overdue.
Remove redundant includes in README [ci skip]

The ActsAsTree module is already included in ActiveRecord::Base.
This fixes #19.