[ADAM-1631] Added a section for homebrew.
[ADAM-1631] Added a section for homebrew.

Resolves #1631.

laserson/adam,heuermh/adam,heuermh/adam,bigdatagenomics/adam,laserson/adam,laserson/adam,heuermh/adam,bigdatagenomics/adam,bigdatagenomics/adam,laserson/adam,heuermh/adam,bigdatagenomics/adam