Merge from vendor branch TNF:
authortaca <taca>
Sat, 17 Dec 2011 17:27:34 +0000 (17:27 +0000)
committertaca <taca>
Sat, 17 Dec 2011 17:27:34 +0000 (17:27 +0000)
commitf8dfd32ccc65bdfdc8d9826e6c6e3cae822cd774
tree6062621df691883b36db5eb2ed72843e716c4924
parent6ddf1c7eff517740ea80872628eaabe716f28831
parent9e770ebe9a80ac3e376535c1136092827cd221e3
Merge from vendor branch TNF:
Importing databases/ruby-dm-is-tree package version 1.2.0.

DataMapper plugin enabling easy creation of tree structures from your DM models.

This requires a foreign key property for your model, which by default would be
called :parent_id.