login = (credentials) =>
    authActions.login(dispatch, firebase, credentials)
Logs user into Firebase. For examples, visit the
[auth section of the docs](https://react-redux-firebase.com/docs/auth.html) or the
[auth recipes section](https://react-redux-firebase.com/docs/recipes/auth.html).
@param {object} credentials - Credentials for authenticating
@param {string} credentials.provider - External provider (google |
facebook | twitter)
@param {string} credentials.type - Type of external authentication
(popup | redirect) (only used with provider)
@param {string} credentials.email - Credentials for authenticating
@param {string} credentials.password - Credentials for authenticating (only used with email)
@param {string} credentials.emailLink - emailLink for authenticating (only used with passwordless sign-in)
@returns {Promise} Containing user's auth data
@see https://react-redux-firebase.com/docs/auth.html#logincredentials
@see https://react-redux-firebase.com/docs/api/firebaseInstance.html#login