Merge pull request #65 from Wollac/chore/travis

Enable Travis CI

.travis.yml

+language: go
+
+go:
+  - 1.12
+
+env:
+  - GO111MODULE=on
+
+# we are using go modules, so there is nothing to install
+install: true

README.md

 # goshimmer
 
+[![Build Status](https://travis-ci.org/iotaledger/goshimmer.svg?branch=master)](https://travis-ci.org/iotaledger/goshimmer)
+
 ## Run Shimmer
 
 First, you need to [install Go](https://golang.org/doc/install) if it is not already installed on your machine. It is recommended that you use the most recent version of Go.