title: How to switch authentication providers seamlessly?
body: <p>I was planning on using firebase auth for authentication (I had already implemented my own strategy but thought it might be easier to use firebase for launch), in the event I ever want to change the authentication provider either to another 3rd party service such as auth0 or back to my own strategy, how could I move users over while keeping password information? </p>
  
  <p>Currently, it seems impossible to do so as firebase doesn't provide me with any information on how the passwords are encrypted. What would be a professional way to handle this? (I've also considered only moving new users to the new authentication provider and writing an abstraction layer that interfaces with the different auth providers)</p>