Updated Readme to contain warning.

README.md

@@ -183,6 +183,9 @@ yarn dx
 1. Click on the `User` model to add a new user record.
 1. Fill out the fields `email`, `username`, `password`, and set `metadata` to empty `{}` (remembering to encrypt your password with [BCrypt](https://bcrypt-generator.com/)) and click `Save 1 Record` to create your first user.
    > New users are set on a `TRIAL` plan by default. You might want to adjust this behavior to your needs in the `apps/web/prisma/schema.prisma` file.
+   
+   > :warning: **Please do not use capitalisation in your email**
+
 1. Open a browser to [http://localhost:3000](http://localhost:3000) and login with your just created, first user.
 
 ### E2E-Testing