text: Title: [Migrated] Slim handler and python decouple problem
  Body: Originally from: https://github.com/Miserlou/Zappa/issues/1513 by [giovannicimolin](https://github.com/giovannicimolin)
  
  <!--- Provide a general summary of the issue in the Title above -->
  When using slim_handler and python-decouple, the zappa app fails to deploy because the .env file is not found by python-decouple.
  
  Python 2.7
  
  ## Expected Behavior
  python-decouple working when using slim_handler.
  
  ## Actual Behavior
  Python-decouple doesn't find the .env file.
  `UndefinedValueError: EMAIL_DEFAULT_FROM not found. Declare it as envvar or define a default value.`
  
  ## Possible Fix
  Change location of .env file when using Slim_handler to include it on the base directory from where python is called.
  
  ## Steps to Reproduce
  1. Use slim_handler and python-decouple
  2. Zappa tail outputs
  `UndefinedValueError: EMAIL_DEFAULT_FROM not found. Declare it as envvar or define a default value.`
  
  ## Your Environment
  <!--- Include as many relevant details about the environment you experienced the bug in -->
  * Zappa version used: Zappa 0.45.1
  * Operating System and Python version: Arch Linux (lastest) - Python 2.7
  * The output of `pip freeze`:
  
  ```
  amqp==2.2.2
  anyjson==0.3.3
  argcomplete==1.9.2
  autopep8==1.3.5
  awsebcli==3.12.4
  base58==0.2.4
  billiard==3.5.0.3
  blessed==1.14.2
  boto3==1.6.19
  botocore==1.9.19
  celery==4.1.0
  cement==2.8.2
  certifi==2018.1.18
  cffi==1.11.5
  cfn-flip==1.0.3
  chardet==3.0.4
  click==6.7
  colorama==0.3.7
  dj-database-url==0.5.0
  dj-static==0.0.6
  Django==1.11.11
  django-celery-beat==1.1.1
  django-celery-results==1.0.1
  django-cors-headers==2.2.0
  django-extra-fields==0.10
  django-filter==1.1.0
  django-queryinspect==1.0.0
  django-rest-auth==0.9.2
  django-rest-framework==0.1.0
  django-silk==3.0.0
  django-simple-history==1.9.0
  django-storages==1.6.6
  django-tables2==1.21.1
  django-toolbelt==0.0.1
  djangorestframework==3.7.7
  djangorestframework-jsonapi==2.4.0
  djangoutils==0.1.1
  dockerpty==0.4.1
  docopt==0.6.2
  docutils==0.14
  durationpy==0.5
  et-xmlfile==1.0.1
  future==0.16.0
  futures==3.1.1
  geopy==1.12.0
  gprof2dot==2016.10.13
  hjson==3.0.1
  idna==2.6
  inflection==0.3.1
  jdcal==1.3
  Jinja2==2.10
  jmespath==0.9.3
  kappa==0.6.0
  kombu==4.1.0
  lambda-packages==0.19.0
  MarkupSafe==1.0
  odfpy==1.3.6
  openpyxl==2.5.1
  pathspec==0.5.5
  placebo==0.8.1
  psycopg2-binary==2.7.4
  pyasn1==0.4.2
  pycodestyle==2.4.0
  pycparser==2.18
  Pygments==2.2.0
  python-dateutil==2.6.1
  python-decouple==3.1
  python-slugify==1.2.4
  pytz==2018.3
  PyYAML==3.12
  redis==2.10.6
  requests==2.18.4
  s3transfer==0.1.13
  semantic-version==2.5.0
  singledispatch==3.4.0.3
  six==1.11.0
  smarturls==0.1.7
  sqlparse==0.2.4
  static3==0.7.0
  tablib==0.12.1
  tabulate==0.7.5
  termcolor==1.1.0
  toml==0.9.4
  tqdm==4.19.1
  troposphere==2.2.1
  unicodecsv==0.14.1
  Unidecode==1.0.22
  urllib3==1.22
  wcwidth==0.1.7
  websocket-client==0.47.0
  Werkzeug==0.12
  whitenoise==3.3.1
  wsgi-request-logger==0.4.6
  xlrd==1.1.0
  xlwt==1.3.0
  zappa==0.45.1
  ```
  
  * Your `zappa_settings.py`: 
  
  ```
  {
      "dev": {
          "aws_region": "us-east-1",
          "django_settings": "appname.settings.production",
          "profile_name": "default",
          "project_name": "appname",
          "runtime": "python2.7",
          "s3_bucket": "zappa-er0hnd366",
          "slim_handler": true
      }
  }
  ```