Add support for -prerelease flag

Allows users to mark a Github Release as a prerelease.

As `CreateRelease` was part of the public API I have introduced a new private func (`publishRelease`) which allows this change to be introduced in a non-breaking fashion.

Author: jonnyreeves

README.md

@@ -19,6 +19,7 @@ Parameters:
 
 Options:
 	-version: Displays version
+	-prerelease: Identify the release as a prerelease
 
 Environment variables:
   DEBUG: Allows you to run github-release in debugging mode. DO NOT do this if you are attempting to upload big files.
@@ -42,4 +43,4 @@ Feel free to inspect this project's [Makefile](https://github.com/c4milo/github-
 
 ![](https://cldup.com/6Slplyys6X.png)
 
- 
+

main.go

@@ -43,6 +43,7 @@ type Release struct {
 }
 
 var verFlag bool
+var prereleaseFlag bool
 
 func init() {
 	log.SetFlags(0)
@@ -59,6 +60,7 @@ func init() {
 	}
 
 	flag.BoolVar(&verFlag, "version", false, "-version")
+	flag.BoolVar(&prereleaseFlag, "prerelease", false, "-prerelease")
 	flag.Parse()
 }
 
@@ -77,6 +79,7 @@ Parameters:
 
 Options:
 	-version: Displays version
+	-prerelease: Identify the release as a prerelease
 
 Environment variables:
   DEBUG: Allows you to run github-release in debugging mode. DO NOT do this if you are attempting to upload big files.
@@ -139,7 +142,15 @@ Please refer to https://help.github.com/articles/creating-an-access-token-for-co
 	branch := flag.Arg(2)
 	desc := flag.Arg(3)
 
-	CreateRelease(tag, branch, desc, filepaths)
+	release := Release{
+		TagName:    tag,
+		Name:       tag,
+		Prerelease: prereleaseFlag,
+		Draft:      false,
+		Branch:     branch,
+		Body:       desc,
+	}
+	publishRelease(release, filepaths)
 	log.Println("Done")
 }
 
@@ -173,8 +184,6 @@ func uploadFile(uploadURL, path string) {
 // CreateRelease creates a Github Release, attaching the given files as release assets
 // If a release already exist, up in Github, this function will attempt to attach the given files to it.
 func CreateRelease(tag, branch, desc string, filepaths []string) {
-	endpoint := fmt.Sprintf("%s/releases", githubAPIEndpoint)
-
 	release := Release{
 		TagName:    tag,
 		Name:       tag,
@@ -183,7 +192,11 @@ func CreateRelease(tag, branch, desc string, filepaths []string) {
 		Branch:     branch,
 		Body:       desc,
 	}
+	publishRelease(release, filepaths)
+}
 
+func publishRelease(release Release, filepaths []string) {
+	endpoint := fmt.Sprintf("%s/releases", githubAPIEndpoint)
 	releaseData, err := json.Marshal(release)
 	if err != nil {
 		log.Fatalln(err)
@@ -196,7 +209,7 @@ func CreateRelease(tag, branch, desc string, filepaths []string) {
 	if err != nil && data != nil {
 		log.Println(err)
 		log.Println("Trying again assuming release already exists.")
-		endpoint = fmt.Sprintf("%s/releases/tags/%s", githubAPIEndpoint, tag)
+		endpoint = fmt.Sprintf("%s/releases/tags/%s", githubAPIEndpoint, release.TagName)
 		data, err = doRequest("GET", endpoint, "application/json", nil, int64(0))
 	}