Avoid assuming the primary key column is called "id"
Added laziness factor.
v5.1.0 preparation:
* fixed generations column type to be integer
* fixed primary_key_type to delegate to the correct Column field (this broke sqlite, at least)
* delegated functionality to the support_attributes (via _ct), rather than re-implementing them in the generator
* made README tell people to use the generator (and deleted the hierarchy class code snippet to simplify things)
edits to make things a bit more concise
Merge remote-tracking branch 'origin/master' into sweet-migrations
edits to make things a bit more concise
more readme edits
Merge branch 'primary_key' of https://github.com/jasoncodes/closure_tree into primary_key
added pr 117 reference. Thanks for the PR!