diff --git a/app/controllers/tutorial.controller.js b/app/controllers/tutorial.controller.js
index 15d0f99..e4729a4 100644
--- a/app/controllers/tutorial.controller.js
+++ b/app/controllers/tutorial.controller.js
@@ -1,152 +1,115 @@
 const db = require("../models");
-const Tutorial = db.tutorials;
-const Op = db.Sequelize.Op;
+const { tutorials: Tutorial, Sequelize: { Op } } = db;
 
-// Create and Save a new Tutorial
-exports.create = (req, res) => {
-  // Validate request
-  if (!req.body.title) {
-    res.status(400).send({
-      message: "Content can not be empty!"
-    });
-    return;
+// Error handler
+const handleError = (res, message, statusCode = 500) => {
+  res.status(statusCode).send({ message });
+};
+
+// Request validation
+const validateRequest = (req, res, fields) => {
+  for (const field of fields) {
+    if (!req.body[field]) {
+      handleError(res, `${field} can not be empty!`, 400);
+      return false;
+    }
   }
+  return true;
+};
 
-  // Create a Tutorial
-  const tutorial = {
-    title: req.body.title,
-    description: req.body.description,
-    published: req.body.published ? req.body.published : false
-  };
+// Create and Save a new Tutorial
+exports.create = async (req, res) => {
+  if (!validateRequest(req, res, ['title'])) return;
 
-  // Save Tutorial in the database
-  Tutorial.create(tutorial)
-    .then(data => {
-      res.send(data);
-    })
-    .catch(err => {
-      res.status(500).send({
-        message:
-          err.message || "Some error occurred while creating the Tutorial."
-      });
-    });
+  try {
+    const tutorial = {
+      title: req.body.title,
+      description: req.body.description,
+      published: req.body.published || false
+    };
+    const data = await Tutorial.create(tutorial);
+    res.send(data);
+  } catch (err) {
+    handleError(res, err.message || "Some error occurred while creating the Tutorial.");
+  }
 };
 
 // Retrieve all Tutorials from the database.
-exports.findAll = (req, res) => {
-  const title = req.query.title;
-  var condition = title ? { title: { [Op.like]: `%${title}%` } } : null;
-
-  Tutorial.findAll({ where: condition })
-    .then(data => {
-      res.send(data);
-    })
-    .catch(err => {
-      res.status(500).send({
-        message:
-          err.message || "Some error occurred while retrieving tutorials."
-      });
-    });
+exports.findAll = async (req, res) => {
+  try {
+    const { title } = req.query;
+    const condition = title ? { title: { [Op.like]: `%${title}%` } } : null;
+    const data = await Tutorial.findAll({ where: condition });
+    res.send(data);
+  } catch (err) {
+    handleError(res, err.message || "Some error occurred while retrieving tutorials.");
+  }
 };
 
 // Find a single Tutorial with an id
-exports.findOne = (req, res) => {
-  const id = req.params.id;
+exports.findOne = async (req, res) => {
+  const { id } = req.params;
 
-  Tutorial.findByPk(id)
-    .then(data => {
-      if (data) {
-        res.send(data);
-      } else {
-        res.status(404).send({
-          message: `Cannot find Tutorial with id=${id}.`
-        });
-      }
-    })
-    .catch(err => {
-      res.status(500).send({
-        message: "Error retrieving Tutorial with id=" + id
-      });
-    });
+  try {
+    const data = await Tutorial.findByPk(id);
+    if (data) {
+      res.send(data);
+    } else {
+      handleError(res, `Cannot find Tutorial with id=${id}.`, 404);
+    }
+  } catch (err) {
+    handleError(res, `Error retrieving Tutorial with id=${id}`);
+  }
 };
 
 // Update a Tutorial by the id in the request
-exports.update = (req, res) => {
-  const id = req.params.id;
+exports.update = async (req, res) => {
+  const { id } = req.params;
 
-  Tutorial.update(req.body, {
-    where: { id: id }
-  })
-    .then(num => {
-      if (num == 1) {
-        res.send({
-          message: "Tutorial was updated successfully."
-        });
-      } else {
-        res.send({
-          message: `Cannot update Tutorial with id=${id}. Maybe Tutorial was not found or req.body is empty!`
-        });
-      }
-    })
-    .catch(err => {
-      res.status(500).send({
-        message: "Error updating Tutorial with id=" + id
-      });
-    });
+  try {
+    const [num] = await Tutorial.update(req.body, { where: { id } });
+    if (num === 1) {
+      res.send({ message: "Tutorial was updated successfully." });
+    } else {
+      handleError(res, `Cannot update Tutorial with id=${id}. Maybe Tutorial was not found or req.body is empty!`, 400);
+    }
+  } catch (err) {
+    handleError(res, `Error updating Tutorial with id=${id}`);
+  }
 };
 
 // Delete a Tutorial with the specified id in the request
-exports.delete = (req, res) => {
-  const id = req.params.id;
+exports.delete = async (req, res) => {
+  const { id } = req.params;
 
-  Tutorial.destroy({
-    where: { id: id }
-  })
-    .then(num => {
-      if (num == 1) {
-        res.send({
-          message: "Tutorial was deleted successfully!"
-        });
-      } else {
-        res.send({
-          message: `Cannot delete Tutorial with id=${id}. Maybe Tutorial was not found!`
-        });
-      }
-    })
-    .catch(err => {
-      res.status(500).send({
-        message: "Could not delete Tutorial with id=" + id
-      });
-    });
+  try {
+    const num = await Tutorial.destroy({ where: { id } });
+    if (num === 1) {
+      res.send({ message: "Tutorial was deleted successfully!" });
+    } else {
+      handleError(res, `Cannot delete Tutorial with id=${id}. Maybe Tutorial was not found!`, 404);
+    }
+  } catch (err) {
+    handleError(res, `Could not delete Tutorial with id=${id}`);
+  }
 };
 
 // Delete all Tutorials from the database.
-exports.deleteAll = (req, res) => {
-  Tutorial.destroy({
-    where: {},
-    truncate: false
-  })
-    .then(nums => {
-      res.send({ message: `${nums} Tutorials were deleted successfully!` });
-    })
-    .catch(err => {
-      res.status(500).send({
-        message:
-          err.message || "Some error occurred while removing all tutorials."
-      });
-    });
+exports.deleteAll = async (req, res) => {
+  try {
+    const nums = await Tutorial.destroy({ where: {}, truncate: false });
+    res.send({ message: `${nums} Tutorials were deleted successfully!` });
+  } catch (err) {
+    handleError(res, err.message || "Some error occurred while removing all tutorials.");
+  }
 };
 
-// find all published Tutorial
-exports.findAllPublished = (req, res) => {
-  Tutorial.findAll({ where: { published: true } })
-    .then(data => {
-      res.send(data);
-    })
-    .catch(err => {
-      res.status(500).send({
-        message:
-          err.message || "Some error occurred while retrieving tutorials."
-      });
-    });
+// Find all published Tutorials
+exports.findAllPublished = async (req, res) => {
+  try {
+    const data = await Tutorial.findAll({ where: { published: true } });
+    res.send(data);
+  } catch (err) {
+    handleError(res, err.message || "Some error occurred while retrieving tutorials.");
+  }
 };