Can't push my Django App to heroku
<p>Hello and excuse my english</p>

<p>This error is weird until now I was able to push my Django app and database to heroku, this was my configuration</p>

<p>project structure:</p>

<pre><code>.
├── apps
│   ├── home
│   │   ├── admin.py
│   │   ├── admin.pyc
│   │   ├── __init__.py
│   │   ├── __init__.pyc
│   │   ├── migrations
│   │   ├── models.py
│   │   ├── models.pyc
│   │   ├── templates
│   │   ├── tests.py
│   │   ├── urls.py
│   │   ├── urls.pyc
│   │   ├── views.py
│   │   └── views.pyc
│   ├── __init__.py
│   ├── __init__.pyc
│   ├── inventario
│   │   ├── admin.py
│   │   ├── admin.pyc
│   │   ├── forms.py
│   │   ├── forms.pyc
│   │   ├── __init__.py
│   │   ├── __init__.pyc
│   │   ├── migrations
│   │   ├── models.py
│   │   ├── models.pyc
│   │   ├── templates
│   │   ├── tests.py
│   │   ├── urls.py
│   │   ├── urls.pyc
│   │   ├── views.py
│   │   └── views.pyc
│   ├── ordenes_trabajo
│   │   ├── admin.py
│   │   ├── admin.pyc
│   │   ├── forms.py
│   │   ├── forms.pyc
│   │   ├── __init__.py
│   │   ├── __init__.pyc
│   │   ├── migrations
│   │   ├── models.py
│   │   ├── models.pyc
│   │   ├── templates
│   │   ├── tests.py
│   │   ├── urls.py
│   │   ├── urls.pyc
│   │   ├── views.py
│   │   └── views.pyc
│   ├── sucursales
│   │   ├── admin.py
│   │   ├── admin.pyc
│   │   ├── forms.py
│   │   ├── forms.pyc
│   │   ├── __init__.py
│   │   ├── __init__.pyc
│   │   ├── migrations
│   │   ├── models.py
│   │   ├── models.pyc
│   │   ├── templates
│   │   ├── tests.py
│   │   ├── urls.py
│   │   ├── urls.pyc
│   │   ├── views.py
│   │   └── views.pyc
│   ├── usuarios
│   │   ├── admin.py
│   │   ├── admin.pyc
│   │   ├── forms.py
│   │   ├── forms.pyc
│   │   ├── __init__.py
│   │   ├── __init__.pyc
│   │   ├── migrations
│   │   ├── models.py
│   │   ├── models.pyc
│   │   ├── templates
│   │   ├── tests.py
│   │   ├── urls.py
│   │   ├── urls.pyc
│   │   ├── views.py
│   │   └── views.pyc
│   └── ventas_cotizaciones
│       ├── admin.py
│       ├── admin.pyc
│       ├── forms.py
│       ├── forms.pyc
│       ├── htmltopdf.py
│       ├── htmltopdf.pyc
│       ├── __init__.py
│       ├── __init__.pyc
│       ├── migrations
│       ├── models.py
│       ├── models.pyc
│       ├── templates
│       ├── tests.py
│       ├── urls.py
│       ├── urls.pyc
│       ├── views.py
│       └── views.pyc
├
├── __init__.py
├── manage.py
├── prerequirements_install.txt
├── Procfile
├── proyecto_www
│   ├── db.sqlite3
│   ├── __init__.py
│   ├
│   ├── README.md
│   ├── settings
│   │   ├── base.py
│   │   ├── base.pyc
│   │   ├── __init__.py
│   │   ├
│   │   ├── local.py
│   │   ├
│   │   ├── production.py
│   │   ├── staging.py
│   │   └── staging.pyc
│   ├── urls.py
│   ├
│   ├── wsgi.py
│   └
├── requirements.txt
├── static
</code></pre>

<p>I splited the settings like this:</p>

<p>settings/base.py</p>

<pre><code>from unipath import Path
import os

BASE_DIR = Path(__file__).ancestor(3)
# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/1.8/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = 'THE SECRET KEY OF MY APP'

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True


ALLOWED_HOSTS = ['*']


# Application definition

DJANGO_APPS = (
   ...
)


LOCAL_APPS = (
   ...
)


THIRD_PARTY_APPS = (
  ...
)

INSTALLED_APPS = DJANGO_APPS + LOCAL_APPS + THIRD_PARTY_APPS

MIDDLEWARE_CLASSES = (
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.auth.middleware.SessionAuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
    'django.middleware.security.SecurityMiddleware',
    'corsheaders.middleware.CorsMiddleware',
    'django.middleware.common.CommonMiddleware',
)

ROOT_URLCONF = 'proyecto_www.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [os.path.join(BASE_DIR,'templates')],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.debug',
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'proyecto_www.wsgi.application'

STATIC_URL = '/static/'
STATICFILES_DIRS=(BASE_DIR,'static',)
MEDIA_URL = '/media/'
MEDIA_ROOT = BASE_DIR.child('media')
# Internationalization
# https://docs.djangoproject.com/en/1.8/topics/i18n/

LANGUAGE_CODE = 'es'

TIME_ZONE = 'UTC'

USE_I18N = True

USE_L10N = True

USE_TZ = True


CORS_ORIGIN_ALLOW_ALL = True

CORS_ALLOW_METHODS = (
       ...
    )
</code></pre>

<p>And the settings/staging.py, which I use for deployment</p>

<pre><code> from .base import *

    DEBUG_TOOLBAR_PATCH_SETTINGS = False
    DEBUG = True
    TEMPLATE_DEBUG = True

    # Database
    # https://docs.djangoproject.com/en/1.8/ref/settings/#databases

    DATABASES = {
       ...

    }


# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/1.8/howto/static-files/

STATIC_ROOT = 'staticfiles'
STATICFILES_STORAGE = 'whitenoise.django.GzipManifestStaticFilesStorage'
</code></pre>

<p>My Procfile is:</p>

<pre><code>web: gunicorn proyecto_www.wsgi --log-file -
</code></pre>

<p>My wsgi.py is:</p>

<pre><code>import os
os.environ.setdefault("DJANGO_SETTINGS_MODULE", "proyecto_www.settings.staging")
from django.core.wsgi import get_wsgi_application
from whitenoise.django import DjangoWhiteNoise
application = DjangoWhiteNoise(get_wsgi_application())
</code></pre>

<p>The initial error was "The SECRET_KEY setting must not be empty"</p>

<p>So I followed the answer here
<a href="https://stackoverflow.com/questions/24071489/django-using-multiple-settings-files-with-heroku">Django. Using multiple settings files with Heroku</a></p>

<p>And use the command:</p>

<pre><code>heroku config:set DJANGO_SETTINGS_MODULE=proyecto_www.settings.staging
</code></pre>

<p>And now I receive this error:</p>

<pre><code> remote:        Successfully installed BeautifulSoup-3.2.1 Django-1.8.4 Pillow-3.0.0 PyPDF2-1.25.1 Unipath-1.1 dj-database-url-0.3.0 dj-static-0.0.6 django-cors-headers-1.1.0 django-datatable-view-0.8.3 django-toolbelt-0.0.1 gunicorn-19.4.1 html5lib-0.9999999 psycopg2-2.6.1 python-dateutil-2.4.2 reportlab-3.2.0 six-1.10.0 static3-0.6.1 wheel-0.24.0 whitenoise-2.0.6 xhtml2pdf-0.0.6 xlwt-0.7.4
remote: 
remote:      $ python manage.py collectstatic --noinput
remote:        Post-processing 'tmp/cache/tmp_app_dir/vendor/ruby-2.3.0/lib/ruby/2.3.0/rdoc/generator/template/darkfish/css/rdoc.css' failed!
remote:        Traceback (most recent call last):
remote:          File "manage.py", line 10, in &lt;module&gt;
remote:            execute_from_command_line(sys.argv)
remote:          File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/__init__.py", line 338, in execute_from_command_line
remote:            utility.execute()
remote:          File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/__init__.py", line 330, in execute
remote:            self.fetch_command(subcommand).run_from_argv(self.argv)
remote:          File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 393, in run_from_argv
remote:            self.execute(*args, **cmd_options)
remote:          File "/app/.heroku/python/lib/python2.7/site-packages/django/core/management/base.py", line 444, in execute
remote:            output = self.handle(*args, **options)
remote:          File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/staticfiles/management/commands/collectstatic.py", line 168, in handle
remote:            collected = self.collect()
remote:          File "/app/.heroku/python/lib/python2.7/site-packages/django/contrib/staticfiles/management/commands/collectstatic.py", line 120, in collect
remote:            raise processed
remote:        whitenoise.django.MissingFileError: The file 'tmp/cache/tmp_app_dir/vendor/ruby-2.3.0/lib/ruby/2.3.0/rdoc/generator/template/darkfish/css/images/wrench_orange.png' could not be found with &lt;whitenoise.django.GzipManifestStaticFilesStorage object at 0x7fe55e8ec4d0&gt;.
remote:        The CSS file 'tmp/cache/tmp_app_dir/vendor/ruby-2.3.0/lib/ruby/2.3.0/rdoc/generator/template/darkfish/css/rdoc.css' references a file which could not be found:
remote:          tmp/cache/tmp_app_dir/vendor/ruby-2.3.0/lib/ruby/2.3.0/rdoc/generator/template/darkfish/css/images/wrench_orange.png
remote:        Please check the URL references in this CSS file, particularly any
remote:        relative paths which might be pointing to the wrong location.
remote: 
remote:  !     Error while running '$ python manage.py collectstatic --noinput'.
remote:        See traceback above for details.
remote: 
remote:        You may need to update application code to resolve this error.
remote:        Or, you can disable collectstatic for this application:
remote: 
remote:           $ heroku config:set DISABLE_COLLECTSTATIC=1
remote: 
remote:        http://devcenter.heroku.com/articles/django-assets
remote: 
remote:  !     Push rejected, failed to compile Python app
</code></pre>