Fix .gitignore: stop tracking ignored files

backend/lib/openzeppelin-contracts/test/helpers/enums.js

@@ -0,0 +1,12 @@
+const { BN } = require('@openzeppelin/test-helpers');
+
+function Enum(...options) {
+  return Object.fromEntries(options.map((key, i) => [key, new BN(i)]));
+}
+
+module.exports = {
+  Enum,
+  ProposalState: Enum('Pending', 'Active', 'Canceled', 'Defeated', 'Succeeded', 'Queued', 'Expired', 'Executed'),
+  VoteType: Enum('Against', 'For', 'Abstain'),
+  Rounding: Enum('Down', 'Up', 'Zero'),
+};