Removed Python 3.3 support and added Python 3.7 support

.travis.yml

@@ -1,10 +1,10 @@
 sudo: required
 language: python
 python:
-  - "3.3"
   - "3.4"
   - "3.5"
   - "3.6"
+  - "3.7"
 services:
   - docker
 install: 

README.md

@@ -1,7 +1,7 @@
 # Dagda
 [![Build Status](https://travis-ci.org/eliasgranderubio/dagda.svg?branch=master)](https://travis-ci.org/eliasgranderubio/dagda)
 [![Coverage Status](https://coveralls.io/repos/github/eliasgranderubio/dagda/badge.svg?branch=master)](https://coveralls.io/github/eliasgranderubio/dagda?branch=master)
-[![Python](https://img.shields.io/badge/python-3.3%2C%203.4%2C%203.5%2C%203.6-blue.svg)](https://github.com/eliasgranderubio/dagda)
+[![Python](https://img.shields.io/badge/python-3.4%2C%203.5%2C%203.6%2C%203.7-blue.svg)](https://github.com/eliasgranderubio/dagda)
 [![Docker Pulls](https://img.shields.io/docker/pulls/3grander/dagda.svg)](https://hub.docker.com/r/3grander/dagda/)
 [![License](https://img.shields.io/badge/license-Apache%202-blue.svg)](https://github.com/eliasgranderubio/dagda)
 [![FOSSA Status](https://app.fossa.io/api/projects/git%2Bgithub.com%2Feliasgranderubio%2Fdagda.svg?type=shield)](https://app.fossa.io/projects/git%2Bgithub.com%2Feliasgranderubio%2Fdagda?ref=badge_shield)