Use entrypoints for app registration

aleksis/apps/postbuero/__init__.py

@@ -5,4 +5,4 @@ try:
 except Exception:
     __version__ = "unknown"
 
-default_app_config = "aleksis.apps.postbuero.apps.DefaultConfig"
+default_app_config = "aleksis.apps.postbuero.apps.PostBueroConfig"

aleksis/apps/postbuero/apps.py

 from aleksis.core.util.apps import AppConfig
 
 
-class postbueroConfig(AppConfig):
+class PostBueroConfig(AppConfig):
     name = "aleksis.apps.postbuero"
     verbose_name = "AlekSIS — Postbuero (Mail server management)"

pyproject.toml

@@ -47,6 +47,13 @@ flake8-isort = "^3.0.0"
 pytest-cov = "^2.8.1"
 pytest-sugar = "^0.9.2"
 
+[tool.poetry.plugins."aleksis.app"]
+postbuero = "aleksis.apps.postbuero.apps:PostBueroConfig"
+
+[tool.black]
+line-length = 100
+exclude = "/migrations/"
+
 [build-system]
 requires = ["poetry>=1.0"]
 build-backend = "poetry.masonry.api"