Fix installation docs
Fix installation docs

pombredanne/grab-1,SpaceAppsXploration/grab,huiyi1990/grab,codevlabs/grab,SpaceAppsXploration/grab,DDShadoww/grab,maurobaraldi/grab,codevlabs/grab,liorvh/grab,lorien/grab,huiyi1990/grab,shaunstanislaus/grab,giserh/grab,shaunstanislaus/grab,kevinlondon/grab,lorien/grab,maurobaraldi/grab,DDShadoww/grab,istinspring/grab,liorvh/grab,istinspring/grab,alihalabyah/grab,pombredanne/grab-1,raybuhr/grab,giserh/grab,raybuhr/grab,alihalabyah/grab,kevinlondon/grab