Fetch all releases when doing `hub release`

As suggested at #1511, instead of fetching only the first 30 releases,
follow the `next` link to fetch all pages.

features/release.feature

@@ -94,6 +94,59 @@ Feature: hub release
       v1.0.2\n
       """
 
+  Scenario: Fetch releases across multiple pages
+    Given the GitHub API server:
+      """
+      get('/repos/mislav/will_paginate/releases') {
+        assert :per_page => "100", :page => :no
+        response.headers["Link"] = %(<https://api.github.com/repositories/12345?per_page=100&page=2>; rel="next")
+        json [
+          { tag_name: 'v1.2.0',
+            name: 'will_paginate 1.2.0',
+            draft: false,
+            prerelease: false,
+          },
+        ]
+      }
+
+      get('/repositories/12345') {
+        assert :per_page => "100"
+        if params[:page] == "2"
+          response.headers["Link"] = %(<https://api.github.com/repositories/12345?per_page=100&page=3>; rel="next")
+          json [
+            { tag_name: 'v1.2.0-pre',
+              name: 'will_paginate 1.2.0-pre',
+              draft: false,
+              prerelease: true,
+            },
+            { tag_name: 'v1.0.2',
+              name: 'will_paginate 1.0.2',
+              draft: false,
+              prerelease: false,
+            },
+          ]
+        elsif params[:page] == "3"
+          json [
+            { tag_name: 'v1.0.0',
+              name: 'will_paginate 1.0.0',
+              draft: false,
+              prerelease: true,
+            },
+          ]
+        else
+          status 400
+        end
+      }
+      """
+      When I successfully run `hub release`
+      Then the output should contain exactly:
+      """
+      v1.2.0
+      v1.2.0-pre
+      v1.0.2
+      v1.0.0\n
+      """
+
   Scenario: Repository not found when listing releases
     Given the GitHub API server:
       """

github/client.go

@@ -274,19 +274,30 @@ type ReleaseAsset struct {
 	ApiUrl      string `json:"url"`
 }
 
-func (client *Client) FetchReleases(project *Project) (response []Release, err error) {
+func (client *Client) FetchReleases(project *Project) (releases []Release, err error) {
 	api, err := client.simpleApi()
 	if err != nil {
 		return
 	}
 
-	res, err := api.Get(fmt.Sprintf("repos/%s/%s/releases", project.Owner, project.Name))
-	if err = checkStatus(200, "fetching releases", res, err); err != nil {
-		return
-	}
+	path := fmt.Sprintf("repos/%s/%s/releases?per_page=100", project.Owner, project.Name)
+
+	releases = []Release{}
+	var res *simpleResponse
 
-	response = []Release{}
-	err = res.Unmarshal(&response)
+	for path != "" {
+		res, err = api.Get(path)
+		if err = checkStatus(200, "fetching releases", res, err); err != nil {
+			return
+		}
+		path = res.Link("next")
+
+		releasesPage := []Release{}
+		if err = res.Unmarshal(&releasesPage); err != nil {
+			return
+		}
+		releases = append(releases, releasesPage...)
+	}
 
 	return
 }