circle: add testing configuration

Initially just test whether we can build.

.circlci/config.yml

@@ -0,0 +1,27 @@
+version: 2
+jobs:
+  build:
+    docker:
+      # CircleCI Go images available at: https://hub.docker.com/r/circleci/golang/
+      - image: circleci/golang:1.11
+
+    working_directory: /go/src/bitbucket.org/ausocean/av
+
+    environment:
+      TEST_RESULTS: /tmp/test-results
+
+    steps:
+      - checkout
+
+      - restore_cache:
+          keys:
+            - v1-pkg-cache
+
+      - run: go get -u ./...
+
+      - run: go build ./...
+
+      - save_cache:
+          key: v1-pkg-cache
+          paths:
+            - "/go/pkg"