added tests checking if fields are in forms (dc,bo,li,su)
rm assets field from support's add-form & code cleaning
rm duplicated tests & code cleaning
rm 'form' string from supports' urls
Merge branch 'develop' of https://github.com/allegro/ralph_assets into rm-assets-field-form-support
added commas, commas, commas..
fixed flake8
Merge pull request #340 from xliiv/rm-assets-field-form-support

Deleted-assets-field
Url to ajax select objects
Merge pull request #342 from quamilek/urls-to-ajax-object

Url to ajax select objects
removed unique on contract_id
added migration
Merge pull request #344 from ar4s/324-non-unique-contract-id

Removed unique on contract_id
Merge branch 'develop' into hostname-use

Conflicts:
	src/ralph_assets/tests/functional/tests_view.py
review fixes