Added CI integration with Travis-CI (#226)

Next steps:

* Go to https://travis-ci.org/
* Click "Sign in with GitHub"
* Click your user icon and click "Accounts"
* Enable for CTFd

.travis.yml

@@ -0,0 +1,8 @@
+language: python
+python:
+    - 2.7
+install:
+    - pip install -r requirements.txt
+    - pip install -r development.txt
+script:
+    - nosetests

README.md

@@ -1,6 +1,7 @@
 ![](https://raw.githubusercontent.com/isislab/CTFd/master/CTFd/static/original/img/logo.png)
 ====
 
+[![Build Status](https://travis-ci.org/isislab/CTFd.svg?branch=master)](https://travis-ci.org/isislab/CTFd)
 [![CTFd Slack](https://slack.ctfd.io/badge.svg)](https://slack.ctfd.io/)
 
 CTFd is a CTF in a can. Easily modifiable and has everything you need to run a jeopardy style CTF.