All kinds of new stuff. Started with perfecting the account controller. [skip ci]

app/lib/Firefly/Helper/Controllers/AccountInterface.php

@@ -0,0 +1,31 @@
+<?php
+
+namespace Firefly\Helper\Controllers;
+
+use Illuminate\Database\Eloquent\Collection;
+
+/**
+ * Interface AccountInterface
+ *
+ * @package Firefly\Helper\Controllers
+ */
+interface AccountInterface
+{
+
+    /**
+     * Build the index:
+     *
+     * @param Collection $accounts
+     *
+     * @return mixed
+     */
+    public function index(Collection $accounts);
+
+    /**
+     * @param Account $account
+     *
+     * @return mixed
+     */
+    public function openingBalanceTransaction(\Account $account);
+
+}