Incorrect Jags command for Fedora Linux

[dhvalden]

There is no binaries for Fedora in the dnf repos. Jags for fedora has to be downloaded

[j-i-l]

@dhvalden thanks for pointing this out.
It seems to me that on Fedora JAGS needs to be installed from source.

Also, when doing so, for some reason it gets installed under /usr/local/lib even on a 64-bit system which is a problem since libraries are expected to be in /usr/local/lib64.
Specifying the libdir explicitly for the configuration fixes this issue, so the installation procedure might look as follows:

wget -O /tmp/jags.tar.gz https://sourceforge.net/projects/mcmc-jags/files/JAGS/4.x/Source/JAGS-4.3.2.tar.gz/download
cd /tmp
tar -xf jags.tar.gz
cd /tmp/JAGS-4.3.2 
./configure --libdir=/usr/local/lib64
make
sudo make install

With #126 we've added the required steps to install JAGS and the rjags for Fedora, and other common operating systems to the README.md.