get the currencies from database rather than hardcoded

erpnext/accounts/report/general_ledger/general_ledger.js

@@ -1,7 +1,25 @@
 // Copyright (c) 2015, Frappe Technologies Pvt. Ltd. and Contributors
 // License: GNU General Public License v3. See license.txt
 
-frappe.query_reports["General Ledger"] = {
+const get_currencies = () => {
+	// frappe.db.get_list returns a Promise
+	return frappe.db.get_list('GL Entry',
+		{
+			distinct: true,
+			fields:['account_currency'],
+			as_list: true
+		}
+	);
+}
+
+const flatten = (array) => {
+	return [].concat.apply([], array);
+}
+
+get_currencies()
+.then((r) => flatten(r))
+.then((currency_list) => {
+	frappe.query_reports["General Ledger"] = {
 		"filters": [
 			{
 				"fieldname":"company",
@@ -110,7 +128,8 @@ frappe.query_reports["General Ledger"] = {
 				"fieldname": "presentation_currency",
 				"label": __("Currency"),
 				"fieldtype": "Select",
-			"options": "NGN\nINR\nUSD"
+				"options": currency_list
 			}
 		]
-}
+	}
+});