Add dev dependencies: linters, formatters, testing

pyproject.toml

@@ -9,3 +9,22 @@ dependencies = [
     "django==4.2",
     "psycopg2-binary>=2.9.10",
 ]
+
+[dependency-groups]
+dev = [
+    "black>=25.1.0",
+    "djlint>=1.36.4",
+    "flake8>=7.1.2",
+    "flake8-bugbear>=24.12.12",
+    "flake8-pyproject>=1.2.3",
+    "isort>=6.0.1",
+    "pytest>=8.3.5",
+    "pytest-django>=4.10.0",
+]
+
+[tool.isort]
+profile = "black"
+known_first_party = "servala"
+
+[tool.flake8]
+max-line-length = 160