Revert "remove migrations"

This reverts commit c2e10884cb994e690ee1d2e7004e4648b33e64cd.

src/migrations/20191102223900-drop-configs-indices.js

@@ -0,0 +1,28 @@
+require('module-alias/register');
+const logger = require('@alias/logger')('growi:migrate:drop-configs-indices');
+
+const mongoose = require('mongoose');
+const config = require('@root/config/migrate');
+
+async function dropIndexIfExists(collection, indexName) {
+  if (await collection.indexExists(indexName)) {
+    await collection.dropIndex(indexName);
+  }
+}
+
+module.exports = {
+  async up(db) {
+    logger.info('Apply migration');
+    mongoose.connect(config.mongoUri, config.mongodb.options);
+
+    const collection = db.collection('configs');
+    await dropIndexIfExists(collection, 'ns_1');
+    await dropIndexIfExists(collection, 'key_1');
+
+    logger.info('Migration has successfully applied');
+  },
+
+  down(db) {
+    // do not rollback
+  },
+};

src/migrations/20191102223901-drop-pages-indices.js

@@ -0,0 +1,29 @@
+require('module-alias/register');
+const logger = require('@alias/logger')('growi:migrate:drop-pages-indices');
+
+const mongoose = require('mongoose');
+const config = require('@root/config/migrate');
+
+async function dropIndexIfExists(collection, indexName) {
+  if (await collection.indexExists(indexName)) {
+    await collection.dropIndex(indexName);
+  }
+}
+
+module.exports = {
+  async up(db) {
+    logger.info('Apply migration');
+    mongoose.connect(config.mongoUri, config.mongodb.options);
+
+    const collection = db.collection('pages');
+    await dropIndexIfExists(collection, 'lastUpdateUser_1');
+    await dropIndexIfExists(collection, 'liker_1');
+    await dropIndexIfExists(collection, 'seenUsers_1');
+
+    logger.info('Migration has successfully applied');
+  },
+
+  down(db) {
+    // do not rollback
+  },
+};