Feat: adding circle ci (#15)

* added circle.yml config

* set maxworkers in circle

* trying diff node versions

* multiple node

* pre nvm install

* testing parallel

* added badge to readme

* clean up circle.yml

README.md

@@ -1,8 +1,10 @@
 # Mercury Parser - Extracting content from chaos
 
+[![CircleCI](https://circleci.com/gh/postlight/readability-parser.svg?style=svg)](https://circleci.com/gh/postlight/readability-parser)
+
 The Mercury Parser extracts the bits that humans care about from any URL you give it. That includes article content, titles, authors, published dates, excerpts, lead images, and more.
 
-The Mercury Parser module powers the [Mercury Parser API](#tk), a free API from [Postlight](https://www.postlight.com/) that puts all of this information one API request away..
+The Mercury Parser module powers the [Mercury Parser API](https://mercury.postlight.com/web-parser/), a free API from [Postlight](https://www.postlight.com/) that puts all of this information one API request away..
 
 ## How? Like this.
 

circle.yml

@@ -0,0 +1,25 @@
+## Customize the test machine
+machine:
+
+  timezone:
+    America/New_York
+
+  node:
+    version:
+      4.3.2
+
+## Customize dependencies
+dependencies:
+  pre:
+    - nvm install 6.9.1
+    - nvm install 7.0.0
+
+## Customize test commands
+test:
+  override:
+    - nvm use 4.3.2 && npm run build && jest --maxWorkers=1:
+        parallel: true
+    - nvm use 6.9 && npm run build && jest --maxWorkers=1:
+        parallel: true
+    - nvm use 7.0 && npm run build && jest --maxWorkers=1:
+        parallel: true