This is an alpha release of Terminix for adventurous folks who are familiar with Linux, otherwise it is recommended to wait for an appropriate distro package to be created.
Note that only a 64 bit version of the application is available, for 32 bit you will need to build the application yourself.
To install the preview release, download the zip file and unzip it to your root as follows:
sudo unzip terminix.zip -d /
Once unzipped, you will need to compile the glib schema as follows:
glib-compile-schemas /usr/share/glib-2.0/schemas/