Add flake8 check in pre-commit

.pre-commit-config.yaml

@@ -18,6 +18,19 @@
     -   id: check-symlinks
     -   id: check-added-large-files
 
+-   repo: local
+    hooks:
+    -   id: flake8
+        name: flake8
+        entry: flake8
+        language: system
+        args:
+        -   --count
+        -   --select=E9,F63,F7,F82
+        -   --show-source
+        -   --statistics
+        files: \.py$
+
 -   repo: local
     hooks:
     -   id: copyright_checker

.travis.yml

 language: python
 
-before_install: pip install flake8
-
-before_script: flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+python:
+- '2.7'
+- '3.5'
+- '3.6'
+- '3.7'
 
 script: /bin/bash ./scripts/check_code_style.sh
 

requirements.txt

@@ -9,3 +9,4 @@ six >= 1.10.0
 chardet == 3.0.4
 requests
 pandas
+flake8