Merge pull request #20 from lcy-seso/add_travis_config

add travis config.

.travis.yml

+language: cpp
+cache: ccache
+sudo: required
+dist: trusty
+os:
+  - linux
+env:
+  - JOB=PRE_COMMIT
+
+addons:
+  apt:
+    packages:
+      - git
+      - python
+      - python-pip
+      - python2.7-dev
+before_install:
+  -  pip install -U virtualenv pre-commit pip
+script:
+  -  .travis/precommit.sh
+notifications:
+  email:
+    on_success: change
+    on_failure: always

.travis/precommit.sh

+#!/bin/bash
+function abort(){
+    echo "Your commit not fit PaddlePaddle code style" 1>&2
+    echo "Please use pre-commit scripts to auto-format your code" 1>&2
+    exit 1
+}
+
+trap 'abort' 0
+set -e
+cd `dirname $0`
+cd ..
+export PATH=/usr/bin:$PATH
+pre-commit install
+
+if ! pre-commit run -a ; then
+  ls -lh
+  git diff  --exit-code
+  exit 1
+fi
+
+trap : 0