extract server-side git commands to constants

lib/api/internal.rb

 module API
   # Internal access API
   class Internal < Grape::API
+
+    DOWNLOAD_COMMANDS = %w{ git-upload-pack git-upload-archive }
+    PUSH_COMMANDS = %w{ git-receive-pack }
+
     namespace 'internal' do
       #
       # Check if ssh key has access to project code
@@ -26,16 +30,16 @@ module API
 
 
         if key.is_a? DeployKey
-          key.projects.include?(project) && git_cmd.starts_with?('git-upload-')
+          key.projects.include?(project) && DOWNLOAD_COMMANDS.include?(git_cmd)
         else
           user = key.user
 
           return false if user.blocked?
 
           action = case git_cmd
-                   when 'git-upload-pack', 'git-upload-archive'
+                   when *DOWNLOAD_COMMANDS
                      then :download_code
-                   when 'git-receive-pack'
+                   when *PUSH_COMMANDS
                      then
                      if project.protected_branch?(params[:ref])
                        :push_code_to_protected_branches