Welcome to RM5248's APT repositories.

To import the GPG key used to sign the files:

wget -q -O - http://apt.rm5248.com/pub.key | sudo apt-key add -

To add to APT sources, edit your /etc/apt/sources.list OR add a new file /etc/apt/sources.list.d/rm5248.list and add the following lines(depending on your distribution):

deb http://nightly.apt.rm5248.com/nightly-jessie jessie main

deb-src http://nightly.apt.rm5248.com/nightly-jessie jessie main

deb http://nightly.apt.rm5248.com/nightly-stretch stretch main

deb-src http://nightly.apt.rm5248.com/nightly-stretch stretch main