feat(ci): add travis yml config for go

progresses #4

.travis.yml

@@ -0,0 +1,11 @@
+matrix:
+  include:
+    - language: go
+      go: "1.11"
+      before_script:
+        - mkdir -p ${UNPROCESSED_IMAGES}
+        - cd api
+      script:
+        - go test ./...
+      env: GO111MODULE=on
+services: mongodb

README.md

@@ -29,7 +29,7 @@ The config params can also be set via environment variables.
 Go into the `api/` folder and run `go get -d ./...` to download the dependencies, followed by `go build` to compile the executable.  
 This project is using [Go Modules](https://github.com/golang/go/wiki/Modules), which were introduced with Go v1.11. So, make sure that the project code is outside your `$GOPATH/src`, or set the environment variable `GO111MODULE=on` when running `go get|build|...`.
 
-#### Running
+#### Execution
 
 Once built the executable can be started with `./api -c=/path/to/config.json`, or, if using env variables, `UNPROCESSED_IMAGES=/path/to/image/dir PORT=3333 DATABASE=tagallery DATABASE_HOST=localhost:27017 ./api`.