Allow installing via NPM

[rishitank]

Hi,

I noticed that you recently added NPM support for this package, however I am unable to find it if I do npm search bootstrap-sortable, or if I try to run npm i --save bootstrap-sortable then npm is unable to find the package. For now I am using your git repo URL in my package.json, but this is not ideal, thanks.

[ole1986]

either through npm or libman would be very helpful