Go to Katenary V3

This is the next-gen of Katenary

doc/docs/packages/update.md

@@ -0,0 +1,55 @@
+<!-- Code generated by gomarkdoc. DO NOT EDIT -->
+
+# update
+
+``` go
+import "katenary/update"
+```
+
+Update package is used to check if a new version of katenary is
+available.
+
+## Variables
+
+``` go
+var Version = "master" // reset by cmd/main.go
+```
+
+## func DownloadFile
+
+``` go
+func DownloadFile(url, exe string) error
+```
+
+DownloadFile will download a url to a local file. It also ensure that
+the file is executable.
+
+## func DownloadLatestVersion
+
+``` go
+func DownloadLatestVersion(assets []Asset) error
+```
+
+DownloadLatestVersion will download the latest version of katenary.
+
+## type Asset
+
+Asset is a github asset from release url.
+
+``` go
+type Asset struct {
+    Name string `json:"name"`
+    URL  string `json:"browser_download_url"`
+}
+```
+
+### func CheckLatestVersion
+
+``` go
+func CheckLatestVersion() (string, []Asset, error)
+```
+
+CheckLatestVersion check katenary latest version from release and
+propose to download it
+
+Generated by [gomarkdoc](https://github.com/princjef/gomarkdoc)