This is a modified version of https://github.com/ThePrimeagen/keyboards.

Installation

PLEASE MAKE A BACKUP OF THE FILES BEFORE EDITING

Add the new layout to the symbols directory Open /usr/share/X11/xkb/symbols/us and add the symbols from file real-prog-dvorak-mod under Dvorak Programmer

Update evdev by opening /usr/share/X11/xkb/rules/evdev.xml

And add the following

<variant>
    <configItem>
        <name>rdvp</name>
        <description>English (Real Programmers Dvorak)</description>
        <vendor>MichaelPaulson</vendor>
    </configItem>
</variant>

To permanently set the layout
Edit /etc/default/keyboard and set the following

...
XKBLAYOUT="us"
XKBVARIANT="rdvp"
...