Add flake8-bugbear and lint all apps

tox.ini

@@ -24,6 +24,7 @@ commands =
 [testenv:linters]
 deps =
     flake8
+    flake8-bugbear
     flake8-colors
     flake8-django
     flake8-import-order
@@ -31,7 +32,7 @@ deps =
     pep8-naming
     pyflakes
 commands =
-    flake8 apps/activity apps/api apps/logs apps/member apps/note apps/permission apps/treasury apps/wei
+    flake8 apps
 
 [flake8]
 ignore = W503, I100, I101