Limit number of concurrent archive_repo jobs to 2.

Gemfile

@@ -122,6 +122,7 @@ gem 'slim'
 gem 'sinatra', require: nil
 gem 'sidekiq', '~> 3.3'
 gem 'sidetiq', '0.6.3'
+gem 'sidekiq-limit_fetch'
 
 # HTTP requests
 gem "httparty"

Gemfile.lock

@@ -547,6 +547,8 @@ GEM
       json
       redis (>= 3.0.6)
       redis-namespace (>= 1.3.1)
+    sidekiq-limit_fetch (2.4.1)
+      sidekiq (>= 2.6.5, < 4.0)
     sidetiq (0.6.3)
       celluloid (>= 0.14.1)
       ice_cube (= 0.11.1)
@@ -769,6 +771,7 @@ DEPENDENCIES
   settingslogic
   shoulda-matchers (~> 2.7.0)
   sidekiq (~> 3.3)
+  sidekiq-limit_fetch
   sidetiq (= 0.6.3)
   simplecov
   sinatra

config/initializers/4_sidekiq.rb

@@ -25,3 +25,5 @@ Sidekiq.configure_client do |config|
     namespace: 'resque:gitlab'
   }
 end
+
+Sidekiq::Queue["archive_repo"].limit = 2