deploy keys support for gitlab-shell api

lib/api/internal.rb

@@ -7,10 +7,14 @@ module Gitlab
       #
       get "/allowed" do
         key = Key.find(params[:key_id])
-        user = key.user
-
         project = Project.find_with_namespace(params[:project])
-        action = case params[:action]
+        git_cmd = params[:action]
+
+        if key.is_deploy_key
+          project == key.project && git_cmd == 'git-upload-pack'
+        else
+          user = key.user
+          action = case git_cmd
                    when 'git-upload-pack'
                      then :download_code
                    when 'git-receive-pack'
@@ -24,6 +28,7 @@ module Gitlab
 
           user.can?(action, project)
         end
+      end
 
       #
       # Discover user by ssh key