Add 'make-email-unique' migration file

resource/migrations/20180926134048-make-email-unique.js

@@ -0,0 +1,46 @@
+'use strict';
+
+require('module-alias/register');
+const logger = require('@alias/logger')('growi:migrate:make-email-unique');
+const mongoose = require('mongoose');
+const config = require('@root/config/migrate');
+
+module.exports = {
+
+  async up(db, next) {
+    logger.info('Start migration');
+    mongoose.connect(config.mongoUri, config.mongodb.options);
+
+    const User = require('@server/models/user')();
+
+    // get all users who has 'deleted@deleted' email
+    const users = await User.find({email: 'deleted@deleted'});
+    if (users.length > 0) {
+      logger.info(`${users.length} users found. Replace email...`, users);
+    }
+
+    // make email unique
+    const promises = users.map(user => {
+      const now = new Date();
+      const deletedLabel = `deleted_at_${now.getTime()}`;
+      user.email = `${deletedLabel}@deleted`;
+      return user.save();
+    });
+    await Promise.all(promises);
+
+    // sync index
+    logger.info('Invoking syncIndexes');
+    await User.syncIndexes();
+
+    await mongoose.disconnect();
+
+    logger.info('Migration has successfully terminated');
+    next();
+  },
+
+  down(db, next) {
+    // do not rollback
+    next();
+  }
+
+};