Add Transaction Merchant management (#686)

* Add basid crud for merchant management

* Tweak UI and add localization

* Fix lint

* Add filtering by merchant

* Add tests

* Add stimulus controller to update avatar in merchant form

* Add line between merchant rows

* Change default merchant color

* Cleanup

app/controllers/transactions_controller.rb

@@ -148,6 +148,6 @@ class TransactionsController < ApplicationController
 
     # Only allow a list of trusted parameters through.
     def transaction_params
-      params.require(:transaction).permit(:name, :date, :amount, :currency, :notes, :excluded, :category_id)
+      params.require(:transaction).permit(:name, :date, :amount, :currency, :notes, :excluded, :category_id, :merchant_id)
     end
 end