Blank page after bundle exec rake dev

[savvygit]

After starting bundle exec rake dev then browse to localhost:8080 is just get blank page with fastlane.ci title and icon

is there a way to debug it ?

Procfile.dev
web: bundle exec rackup --host 0.0.0.0 --port 8080 --env development
worker: bundle exec ruby agent/service.rb

$ bundle exec rake dev
foreman start -f Procfile.dev
16:50:25 web.1 | started with pid 29950
16:50:25 worker.1 | started with pid 29951
16:50:29 web.1 | warning: parser/current is loading parser/ruby25, which recognizes
16:50:29 web.1 | warning: 2.5.0-compliant syntax, but you are running 2.5.1.
16:50:29 web.1 | warning: please see https://github.com/whitequark/parser#compatibility-with-ruby-mri.
16:51:31 web.1 | 127.0.0.1 - - [02/Sep/2018:16:51:31 +0200] "GET / HTTP/1.1" 304 - 0.0261
16:51:31 web.1 | 127.0.0.1 - - [02/Sep/2018:16:51:31 +0200] "GET /inline.bundle.js HTTP/1.1" 304 - 0.0042
16:51:31 web.1 | 127.0.0.1 - - [02/Sep/2018:16:51:31 +0200] "GET /polyfills.bundle.js HTTP/1.1" 304 - 0.0043
16:51:31 web.1 | 127.0.0.1 - - [02/Sep/2018:16:51:31 +0200] "GET /styles.bundle.js HTTP/1.1" 304 - 0.0125
16:51:31 web.1 | 127.0.0.1 - - [02/Sep/2018:16:51:31 +0200] "GET /vendor.bundle.js HTTP/1.1" 304 - 0.0054
16:51:31 web.1 | 127.0.0.1 - - [02/Sep/2018:16:51:31 +0200] "GET /main.bundle.js HTTP/1.1" 304 - 0.0056
16:51:31 web.1 | 127.0.0.1 - - [02/Sep/2018:16:51:31 +0200] "GET /favicon.ico HTTP/1.1" 200 32038 0.0071
16:51:32 web.1 | 127.0.0.1 - - [02/Sep/2018:16:51:32 +0200] "GET / HTTP/1.1" 304 - 0.0039
16:51:32 web.1 | 127.0.0.1 - - [02/Sep/2018:16:51:32 +0200] "GET /favicon.ico HTTP/1.1" 200 32038 0.0071