[WIP] change hostname transition
hostname get template vars
Merge branch 'develop' of github.com:allegro/ralph_assets into feature/hostname-transition

Conflicts:
	src/ralph_assets/models_assets.py
added generate_doc signal & handler for it generate_doc_handler
Update settings, fix country_id error, add migrations
Merge pull request #359 from ar4s/refactor-generate-hostname

Refactor generate_hostname
Merge branch 'develop' of github.com:allegro/ralph_assets into feature/hostname-transition

Conflicts:
	src/ralph_assets/models_assets.py
Fix can_generate_hostname
Add test for change_hostname transition
Merge remote-tracking branch 'tymek/post-hook' into develop
Fix flake8 errors
Merge branch 'develop' of https://github.com/allegro/ralph_assets into post-hook
Fix tests - change hostname transition
Remove can_generate_hostname property from Asset model
post transition as signal instead of fn calling signal
Merge branch 'feature/hostname-transition' of https://github.com/quamilek/ralph_assets into post-hook

Conflicts:
	src/ralph_assets/views/transition.py
Check category has code in change hostname transition
added tests; dirty version
Change hostname transition - add tests
added test 'post_transition fails' & code cleanups