Wercker setup environment takes too long and make

问题:

I made a docker image to use it with my builds of a project in Wercker, I did this because I thought having the require packages already installed in the environment is better than installing them in each build of my project.

However, now Wercker fails every time it have to build my project, the reason? timeout because the setup environment step takes more than 5 minutes.

Running wercker version: 1.0.405 (Compiled at: 2016-02-10T22:17:21Z, Git commit: b44ceb57f107c85dbaa619c6d89592b979f69b5b)
Using config:
box: shackra/latex-ebook
build:
steps:
- script:
name: Documento en formato PDF
code: |
xelatex --version
# twice, please
xelatex biblia.tex
xelatex biblia.tex
- script:
name: Subir documentos a Bitbucket
code: |
./upload-to-bitbucket.sh $BITBUCKET_U $BITBUCKET_P /straubingerdigital/biblia-platense/downloads biblia.pdf

Pulling from shackra/latex-ebook: latest
Pulling fs layer: e627a276e4dc
Pulling fs layer: 16c1e3a61000
Pulling fs layer: 80bc33a4179a
Pulling fs layer: d23822bfcf6d
Pulling fs layer: 4fdf7f1f2966
Pulling fs layer: f6a9cd9eb099
Pulling fs layer: 85a462562b69
Pulling fs layer: 73a2d7fa1951
Pulling fs layer: 56fffce111ea
Verifying Checksum: 16c1e3a61000
Download complete: 16c1e3a61000
Verifying Checksum: 56fffce111ea
Download complete: 56fffce111ea
Verifying Checksum: 80bc33a4179a
Download complete: 80bc33a4179a
Verifying Checksum: d23822bfcf6d
Download complete: d23822bfcf6d
Verifying Checksum: 4fdf7f1f2966
Download complete: 4fdf7f1f2966
Verifying Checksum: 85a462562b69
Download complete: 85a462562b69
Verifying Checksum: 73a2d7fa1951
Download complete: 73a2d7fa1951
Verifying Checksum: e627a276e4dc
Download complete: e627a276e4dc
Pull complete: e627a276e4dc
Pull complete: 16c1e3a61000
Pull complete: 80bc33a4179a
Pull complete: d23822bfcf6d
Pull complete: 4fdf7f1f2966
Verifying Checksum: f6a9cd9eb099
Download complete: f6a9cd9eb099
Pull complete: f6a9cd9eb099
Pull complete: 85a462562b69
Pull complete: 73a2d7fa1951
Pull complete: 56fffce111ea
Digest: sha256:af688a72e89b3a97b5b4d28509291a30be7a6d4b0067180f46f5d97da22679c8
Status: Downloaded newer image for shackra/latex-ebook:latest

It just stays there at Status: Downloaded newer image for shackra/latex-ebook:latest, what is going wrong here? is something I can fix from my Wercker configuration file?