* Remove invalid link in debian docker file.
Remove self-referential link from debian docker setup.
Fixes bug introduced in commit 8c4a50785
* Add Vagrantfile to create CentOS 8 system for deploying open5GS.
This Vagrantfile is identical to the base CentOS 8 box from Vagrant
Cloud, but was modified to increase the amount of virtual memory to
1GB from 512MB.
* Update installation instructions for CentOS 8.
Update the installation instructions for CentOS 8 to describe
step-by-step the commands necessary to install the necessary
prerequesites for building and running Open5GS, installing and building
the source code, and running the base tests to confirm that Open5GS
was built correctly.
