.travis.yml: Include lint stage

Author: ayan-b

.travis.yml

@@ -10,18 +10,33 @@ install:
 stages:
   - test
   - moban
+  - lint
+
+.disable_global: &disable_global
+  before_install: false
+  install: true
+  before_script: false
+  after_success: false
+  after_failure: false
+
+.lint: &lint
+  <<: *disable_global
+  python: 3.6
+  stage: lint
+  install: pip install flake8
+  script: flake8
 
 jobs:
   include:
     - stage: moban
       script:
         - make
         - git diff --exit-code
+    - *lint
 
 stage: test
 
 script:
   - find templates/ -type f -name '*.jj2' -exec echo '{}' \;|sed -e "s/templates\//{%include \"/" -e "s/$/\" %}/" > test.file
   - moban -c config/data.yml -t test.file -td templates .
   - pytest
-  - flake8