Band Scaffold added - Link to index on homepage

[#39944711]
Scope by letter added on index page

[#39944711]
HTML response only in controller - Views done

[#39944711]
Errors helper

[#39944711]
Translations added

[#39944711]
Search form added

[#39944711]
I18n again

[#39944711]
Tests added for Band entity

[#39944711]
Gem thin added

[#39944711]
Tests added for error messages helper

[#39944711]
Merge pull request #6 from WilfriedDeluche/band-entity-39944711

[Fixes #39944711] Band entity 39944711
Solves conflicts