add npm install instructions
add npm install instructions

yads/ngTinyScrollbar,BHASKARSDEN277GITHUB/ngTinyScrollbar,chmieludaniel/ngTinyScrollbar,saike/ngTinyScrollbar,saike/ngTinyScrollbar,BHASKARSDEN277GITHUB/ngTinyScrollbar,yads/ngTinyScrollbar,ccheung0926/ngTinyScrollbar,chmieludaniel/ngTinyScrollbar,ccheung0926/ngTinyScrollbar