Cloudfoundry - Buildpack compilation step failed

Staging app and tracing logs…
   Creating container
   Successfully created container
   Downloading app package…
   Downloaded app package (1.3K)
   -----> Download go 1.9.1
   -----> Running go build supply
   -----> Ruby Buildpack version 1.7.7
   -----> Supplying Ruby
Error staging application: App staging failed in the buildpack compile phase
FAILED