Transform Register call to async/await

[igeligel]

Issue Summary:

In the auth.module.js here you have got some code like:

[REGISTER](context, credentials) {
  return new Promise((resolve, reject) => {
    ApiService.post("users", { user: credentials })
      .then(({ data }) => {
        context.commit(SET_AUTH, data.user);
        resolve(data);
      })
      .catch(({ response }) => {
        context.commit(SET_ERROR, response.data.errors);
        reject(response);
      });
  });
}

Those promise calls could be simplified with async and await calls.

Resources:

• MDN - async function
• javascript.info - async tutorial
• Jest - An Async Example
• Jest - Mock Functions
• Jest - Manual Mocks

Acceptance Criteria:

• A test is introduced, this is perfect work for TDD
• There is no .then(... or .catch(... block or any promise like structure

The main issue can be found here #5

[moozzyk]

I can take this one.