little changes

src/account/auth_pipeline.py

src/account/migrations/0001_initial.py

src/account/migrations/0002_profile_role.py

src/account/migrations/0003_auto_20190106_1846.py

src/account/migrations/0004_auto_20190107_2218.py

src/account/models.py

src/document/migrations/0001_initial.py

src/document/migrations/0002_auto_20190113_1239.py

src/document/migrations/0003_document_solution.py

src/document/migrations/0004_auto_20190114_2016.py

src/document/models.py

src/homework/migrations/0001_initial.py

src/homework/migrations/0002_auto_20190105_1922.py

src/homework/migrations/0003_auto_20190113_1239.py

src/homework/migrations/0004_auto_20190114_1641.py

src/homework/migrations/0005_auto_20190114_1658.py

src/homework/migrations/0006_auto_20190114_1938.py

src/homework/models.py

src/homework/serializers.py

src/news/migrations/0001_initial.py