chore(pep8): implement pep8 standards on codebase

 install flake8 and create .flake8 config file
- add flake8 script to .travis.yml
- fix pep8 errors on codebase

[Finishes #164243636]

.flake8

@@ -0,0 +1,4 @@
+[flake8]
+ignore = W3921
+max-line-length = 160
+exclude = */tests/* */settings/*

.travis.yml

@@ -15,6 +15,7 @@ script:
   - python manage.py migrate --settings=authors.settings.test 
   - coverage run --source=authors.apps ./manage.py test --settings=authors.settings.test
   - coverage
+  - find ./authors/ -name \*.py -exec flake8 {} +
 
 after_success:
   - coverallslanguage: python

requirements.txt

@@ -1,12 +1,32 @@
+astroid==2.2.0
+autopep8==1.4.3
+certifi==2018.11.29
+chardet==3.0.4
 coverage==4.5.2
 coveralls==1.6.0
 dj-database-url==0.5.0
 Django==2.1.7
 django-cors-middleware==1.3.1
 django-extensions==2.1.6
 djangorestframework==3.9.1
+docopt==0.6.2
+entrypoints==0.3
+flake8==3.7.7
 gunicorn==19.9.0
+idna==2.8
+isort==4.3.9
+lazy-object-proxy==1.3.1
+mccabe==0.6.1
 psycopg2-binary==2.7.7
+pycodestyle==2.5.0
+pyflakes==2.1.0
 PyJWT==1.4.2
+pylint==2.3.0
 python-decouple==3.1
+pytz==2018.9
+requests==2.21.0
+six==1.10.0
+typed-ast==1.3.1
+urllib3==1.24.1
 whitenoise==4.1.2
+wrapt==1.11.1