heroku deployment issue

[febilva]

i have referenced this tutorial for heroku deployment Deploying Elixir with Heroku
but it gave me this error.any idea how to fix this?

remote: -----> Creating .profile.d with env vars
remote: -----> Writing export for multi-buildpack support
remote: -----> Phoenix app detected
remote: 
remote: -----> Loading configuration and environment
remote:        Loading config...
remote:        Detecting assets directory
remote:        WARNING: no package.json detected in root nor custom directory
remote:        * assuming phoenix 1.3.x and later, please check config file
remote:        Will use phoenix configuration:
remote:        * assets path assets
remote:        * mix tasks namespace phx
remote:        Will use the following versions:
remote:        * Node 5.3.0
remote:        Will export the following config vars:
remote: APP_URL
remote: DATABASE_URL
remote: POOL_SIZE
remote: SECRET_KEY_BASE
remote:        * MIX_ENV=prod
remote: 
remote: -----> Installing binaries
remote:        Downloading node 5.3.0...
remote:        Installing Node 5.3.0...
remote:        Using default npm version
remote: 
remote: -----> Building dependencies
remote:        Installing and caching node modules
remote: /app/tmp/buildpacks/abc8fb9e8be131ec2574c4ba9e31b81540d97b3bbce47d96e05959c4f81404ac71605dd35ebbcf7a1abe958c346d8ee266ff035de9254424eb54e8b9480059be/lib/build.sh: line 105: cd: /tmp/build_f26475149c0a158cb477053757c3ab1b/./assets: No such file or directory
remote:  !     Push rejected, failed to compile Phoenix app.
remote: 
remote:  !     Push failed
remote: Verifying deploy...

[toreal]

try
gjaldon/heroku-buildpack-phoenix-static#63