remove unused db.py and add flake8 config

.flake8

@@ -0,0 +1,7 @@
+[flake8]
+# Rule definitions: http://flake8.pycqa.org/en/latest/user/error-codes.html
+# W503: line break before binary operator
+exclude = venv*,__pycache__,node_modules,cache,migrations
+ignore = W503
+max-complexity = 14
+max-line-length = 120