Added check_assignee method to Repositories

lib/octokit/client/repositories.rb

@@ -605,6 +605,19 @@ def repository_assignees(repo, options={})
       end
       alias :repo_assignees :repository_assignees
 
+      # Check to see if a particular user is an assignee for a repository.
+      #
+      # @param repo [String, Hash, Repository] A GitHub repository.
+      # @param assignee [String] User login to check
+      # @return [Boolean] True if assignable on project, false otherwise.
+      # @see Octokit::Client
+      # @see http://developer.github.com/v3/issues/assignees/#check-assignee
+      # @example
+      #   Octokit.check_assignee('pengwynn/octokit', 'andrew')
+      def check_assignee(repo, assignee, options={})
+        boolean_from_response(:get, "repos/#{Repository.new repo}/assignees/#{assignee}", options)
+      end
+
       # List watchers subscribing to notifications for a repo
       #
       # @param repo [String, Hash, Repository] A GitHub repository.

spec/octokit/client/repositories_spec.rb

@@ -458,6 +458,17 @@
 
   end
 
+  describe ".check_assignee" do
+
+    it "checks to see if a particular user is an assignee for a repository" do
+      stub_get("/repos/pengwynn/octokit/assignees/andrew").
+      to_return(:status => 204)
+      is_assignee = @client.check_assignee("pengwynn/octokit", 'andrew')
+      expect(is_assignee).to eq(true)
+    end
+
+  end
+
   describe ".subscribers" do
 
     it "lists all the users watching the repository" do