add isort + black + flake8 pre-comit hooks

Author: janosh

.pre-commit-config.yaml

@@ -0,0 +1,15 @@
+repos:
+  - repo: https://github.com/pre-commit/mirrors-isort
+    rev: v4.3.21
+    hooks:
+      - id: isort
+        language_version: python3.7
+  - repo: https://github.com/ambv/black
+    rev: stable
+    hooks:
+      - id: black
+        language_version: python3.7
+  - repo: https://github.com/pre-commit/pre-commit-hooks
+    rev: v2.3.0
+    hooks:
+      - id: flake8

requirements_dev.txt

@@ -1,3 +1,7 @@
 # Requirements of this dev
 FireWorks==1.8.7
-GitPython==2.1.11
+GitPython==2.1.11
+black==19.3b0
+flake8==3.7.8
+isort==4.3.21
+pre-commit==1.18.3