Updated wercker file

wercker.yml

 box: wercker/golang
 
+build:
+  steps:
+    # Workspace
+    - setup-go-workspace
+    - script:
+        name: go get
+        code: |
+          cd $WERCKER_SOURCE_DIR
+          go version
+          go get -t ./...
+    # Build the project
+    - script:
+        name: go build
+        code: |
+          go build ./...
+    # Test the project
+    - script:
+        name: go test
+        code: |
+          go test ./...
+    # npm install
+    - npm-install:
+      cwd: grafana/
+