improve documentation of package definition
improve documentation of package definition

jwhitcraft/sinatra-assetpack,flywithmemsl/sinatra-assetpack,flywithmemsl/sinatra-assetpack,rstacruz/sinatra-assetpack,flywithmemsl/sinatra-assetpack,jwhitcraft/sinatra-assetpack,rstacruz/sinatra-assetpack,jwhitcraft/sinatra-assetpack,rstacruz/sinatra-assetpack