travis and circle-ci integrations (#49)

This adds travis and circleci config files to the repository.

.circleci/config.yml

@@ -0,0 +1,29 @@
+version: 2
+jobs:
+  build:
+    docker:
+      # specify the version you desire here
+      - image: circleci/node:4
+      - image: circleci/node:6
+      - image: circleci/node:latest
+
+    working_directory: ~/repo
+
+    steps:
+      - checkout
+      - restore_cache:
+          keys:
+          - v1-dependencies-{{ checksum "package.json" }}
+          # fallback to using the latest cache if no exact match is found
+          - v1-dependencies-
+
+      - run: npm install
+
+      - save_cache:
+          paths:
+            - node_modules
+          key: v1-dependencies-{{ checksum "package.json" }}
+
+      - run: npm test
+
+

.travis.yml

@@ -0,0 +1,10 @@
+language: node_js
+node_js:
+    - "node"
+    - "6"
+    - "4"
+
+
+install:
+    - npm install
+

README.md

@@ -1,3 +1,4 @@
+[![Build Status](https://travis-ci.org/trivago/parallel-webpack.svg?branch=master)](https://travis-ci.org/trivago/parallel-webpack) [![CircleCI](https://circleci.com/gh/trivago/parallel-webpack.svg?style=svg)](https://circleci.com/gh/trivago/parallel-webpack)
 # parallel-webpack - Building multi-configs in parallel
 
 `parallel-webpack` allows you to run multiple webpack builds in parallel,