Enable side-loading of has_many, through associated resources.

Fix nested links within returned objects to enable has many through relationships.

Fix href with filters for has_many, :through resources

Fix spelling mistake.

Update has_many, through ids in links to be strings instad of numbers

Update spec
Merge pull request #80 from thesteady/enable_has_many_through_side_loading

Enable side-loading of has_many, through associated resources.
v0.4.28
v0.5.0
added :singular_key and :plural_key
Merge pull request #86 from RestPack/gj/add-singular-and-plural-key

added :singular_key and :plural_key
v0.5.1
Fix small typo in README
Merge pull request #87 from JohnKellyFerguson/readme-typo

Fix small typo in README