Add installation doc to docs2
Add installation doc to docs2

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