add gofmt to travis

.travis.gofmt.sh

@@ -0,0 +1,7 @@
+#!/bin/bash
+
+if [ -n "$(gofmt -l .)" ]; then
+    echo "Go code is not formatted:"
+    gofmt -d .
+    exit 1
+fi

.travis.yml

@@ -8,6 +8,7 @@ install:
   - mv github.com/simple-rules/harmony-benchmark ./
   - cd harmony-benchmark
   - go get github.com/go-stack/stack
+  - ./.travis.gofmt.sh
   - go build
 notifications:
   slack: