diff --git a/src/db/index.js b/src/db/index.js
new file mode 100644
index 0000000..b9eb597
--- /dev/null
+++ b/src/db/index.js
@@ -0,0 +1,71 @@
+import mongoose from 'mongoose';
+
+import UserModel from './user.model';
+import logger from '../logger';
+import config from '../config';
+
+
+const options = {
+  useNewUrlParser: true,
+  user: config.database.user,
+  pass: config.database.password,
+};
+
+mongoose.connect(config.database.host, options);
+mongoose.set('useFindAndModify', false);
+
+const db = mongoose.connection;
+
+db.on('error', (err) => logger.error(err));
+db.once('open', () => logger.info('Database connected'));
+
+
+export const initUser = (id) => (
+  new Promise((resolve, reject) => {
+    UserModel.findOneAndUpdate({ id }, { id }, { upsert: true }, (err, doc) => {
+      if (err) {
+        logger.error(err);
+        reject(err);
+      }
+
+      resolve(doc);
+    });
+  })
+);
+
+
+export const setCity = (userId, cityId) => {
+  const document = {
+    city: {
+      id: cityId,
+    },
+  };
+
+  return new Promise((resolve, reject) => {
+    UserModel.findOneAndUpdate({ id: userId }, document, { new: true }, (err, doc) => {
+      if (err) {
+        logger.error(err);
+        reject(err);
+      }
+
+      resolve(doc);
+    });
+  });
+};
+
+
+export const findAssociedCity = (id) => (
+  new Promise((resolve, reject) => {
+    UserModel.findOne({ id }, (err, doc) => {
+      if (err) {
+        logger.error(err);
+        reject(err);
+      }
+
+      resolve(doc.city.id);
+    });
+  })
+);
+
+
+export { UserModel };