release v2.0.0

Merge pull request eldarion#33 from eldarion/django-20

Add Django v1.11, 2.0 support

update changelog for 0.15.0

update changelog for 0.14.0

update changelog for 0.13.0

0.12.0 - fix broken migrations from 0.11.0

Merge pull request eldarion#26 from eldarion/rating-field

Add support for Rating field type

release 0.10.2

Merge pull request eldarion#24 from eldarion/field-missing-likert-scale

Fix Field.form_field() exception

Merge pull request eldarion#23 from eldarion/add-likert

Add likert-style presentation