initial drone CI config

.drone.yml

+kind: pipeline
+name: default
+type: docker
+
+steps:
+- name: test
+  image: golang
+  volumes:
+  - name: deps
+    path: /go
+  commands:
+  - go test
+
+- name: build
+  image: golang
+  volumes:
+  - name: deps
+    path: /go
+  commands:
+  - go build
+
+volumes:
+- name: deps
+  temp: {}