Added appveyor, trying to test if a windows CI build will be possible

.bra.toml

 [run]
 init_cmds = [
-  ["go", "build", "-o", "./bin/grafana-server"],
-	["./bin/grafana-server"]
+  ["go", "build", "-o", "./bin/grafana-server.exe"],
+	["./bin/grafana-server.exe"]
 ]
 watch_all = true
 watch_dirs = [
@@ -12,6 +12,6 @@ watch_dirs = [
 watch_exts = [".go", ".ini"]
 build_delay = 1500
 cmds = [
-  ["go", "build", "-o", "./bin/grafana-server"],
-	["./bin/grafana-server"]
+  ["go", "build", "-o", "./bin/grafana-server.exe"],
+	["./bin/grafana-server.exe"]
 ]

appveyor.yml

+version: "{build}"
+
+os: Windows Server 2012 R2
+
+clone_folder: c:\gopath\src\github.com\grafana\grafana
+
+environment:
+  GOPATH: c:\gopath
+
+install:
+  - echo %PATH%
+  - echo %GOPATH%
+  - go version
+  - go env
+  - go get -v -t ./...
+
+build_script:
+  - go test -v ./pkg/...