Add pre-commit

.pre-commit-config.yaml

@@ -0,0 +1,21 @@
+-   repo: git://github.com/pre-commit/pre-commit-hooks
+    sha: v0.9.1
+    hooks:
+    -   id: check-added-large-files
+    -   id: check-docstring-first
+    -   id: check-merge-conflict
+    -   id: check-yaml
+    -   id: end-of-file-fixer
+    -   id: flake8
+        args:
+            - --exclude=__init__.py
+        language_version: python3
+    -   id: autopep8-wrapper
+        language_version: python3
+    -   id: requirements-txt-fixer
+    -   id: trailing-whitespace
+-   repo: git://github.com/asottile/reorder_python_imports
+    sha: v0.3.5
+    hooks:
+    -   id: reorder-python-imports
+        language_version: python3