docs: Readme (#1484)

### How do I change the amount of CPU or RAM?

  By default, the container will be allowed to use a maximum of 2 CPU cores and 4 GB of RAM.

  By default, Windows will be allowed to use 2 CPU cores and 4 GB of RAM.

  If you want to adjust this, you can specify the desired amount using the following environment variables:

### How do I configure the username and password?

  By default, a user called `Docker` is created during installation and its password is `admin`.

  By default, a user called `Docker` is created and its password is `admin`.

  If you want to use different credentials, you can configure them in your compose file (only before installation):

  If you want to use different credentials during installation, you can configure them in your compose file:

  ```yaml

  environment:

  By default, the English version of Windows will be downloaded.

  But before installation you can add the `LANGUAGE` environment variable to your compose file, in order to specify an alternative language:

  But you can add the `LANGUAGE` environment variable to your compose file, in order to specify an alternative language to be downloaded:

  ```yaml

  environment:

### How do I select the keyboard layout?

  If you want to use a keyboard layout or locale that is not the default for your selected language, you can add  `KEYBOARD` and `REGION` variables like this (before installation):

  If you want to use a keyboard layout or locale that is not the default for your selected language, you can add  `KEYBOARD` and `REGION` variables like this:

  ```yaml

  environment:

    KEYBOARD: "en-US"

  ```

### How do I select the edition?

  Windows Server offers a minimalistic Core edition without a GUI. To select those non-standard editions, you can add a `EDITION` variable like this (before installation):

  ```yaml

  environment:

    EDITION: "core"

  ```

### How do I install a custom image?

  In order to download an unsupported ISO image, specify its URL in the `VERSION` environment variable: