update installation doc
update installation doc

lahmizzar/docs-1,claudsonm/docs,claudsonm/docs,JesusisFreedom/docs,lahmizzar/docs-1,JesusisFreedom/docs,gantry/docs,mariantanase/docs,mariantanase/docs,claudsonm/docs,hennysmafter/docs,mariantanase/docs,lahmizzar/docs-1,gantry/docs,JesusisFreedom/docs,hennysmafter/docs