Add Gentoo installation instructions.
Add Gentoo installation instructions.

fabiokung/passenger-debian,bf4/passenger,clemensg/passenger,clemensg/passenger,phusion/passenger,cgvarela/passenger,antek-drzewiecki/passenger,cgvarela/passenger,bf4/passenger,jawj/passenger,gravitystorm/passenger,kewaunited/passenger,antek-drzewiecki/passenger,kewaunited/passenger,phusion/passenger,clemensg/passenger,phusion/passenger,antek-drzewiecki/passenger,phusion/passenger,bf4/passenger,bf4/passenger,openSUSE/passenger,gravitystorm/passenger,erikogan/passenger,pkmiec/passenger,openSUSE/passenger,antek-drzewiecki/passenger,cgvarela/passenger,cgvarela/passenger,gravitystorm/passenger,fabiokung/passenger-debian,pkmiec/passenger,jawj/passenger,erikogan/passenger,openSUSE/passenger,fabiokung/passenger-debian,gravitystorm/passenger,jawj/passenger,kewaunited/passenger,jawj/passenger,phusion/passenger,kewaunited/passenger,jawj/passenger,antek-drzewiecki/passenger,antek-drzewiecki/passenger,clemensg/passenger,gravitystorm/passenger,cgvarela/passenger,erikogan/passenger,fabiokung/passenger-debian,bf4/passenger,erikogan/passenger,kewaunited/passenger,phusion/passenger,gravitystorm/passenger,antek-drzewiecki/passenger,fabiokung/passenger-debian,clemensg/passenger,cgvarela/passenger,jawj/passenger,clemensg/passenger,openSUSE/passenger,bf4/passenger,kewaunited/passenger,antek-drzewiecki/passenger,erikogan/passenger,fabiokung/passenger-debian,bf4/passenger,openSUSE/passenger,jawj/passenger,clemensg/passenger,cgvarela/passenger,phusion/passenger,pkmiec/passenger,pkmiec/passenger,cgvarela/passenger,clemensg/passenger,pkmiec/passenger,erikogan/passenger,pkmiec/passenger,kewaunited/passenger,openSUSE/passenger,kewaunited/passenger,phusion/passenger,pkmiec/passenger