Edit collection (#173)

* Collection edit modal

* Add icon

* 💚

* Oh look, some specs

* Delete collection

* Remove from collection

* Handle error responses
Protect against deleting last collection

* Fix key

* 💚

* Keyboard navigate documents list

* Add missing database constraints

frontend/styles/constants.js

@@ -41,6 +41,7 @@ export const color = {
 
   /* Brand */
   primary: '#2B8FBF',
+  danger: '#D0021B',
 
   /* Dark Grays */
   slate: '#9BA6B2',