Added git gc for housekeeping

README.md

@@ -121,6 +121,10 @@ Remove tag:
 
     ./bin/gitlab-projects rm-tag gitlab/gitlab-ci.git v3.0.0
 
+Gc repo:
+
+    ./bin/gitlab-projects gc gitlab/gitlab-ci.git
+
 ## Keys
 
 Add key:

lib/gitlab_projects.rb

@@ -60,6 +60,7 @@ class GitlabProjects
     when 'import-project'; import_project
     when 'fork-project'; fork_project
     when 'update-head'; update_head
+    when 'gc'; gc
     else
       $logger.warn "Attempt to execute invalid gitlab-projects command #{@command.inspect}."
       puts 'not allowed'
@@ -246,4 +247,10 @@ class GitlabProjects
     $logger.info "Update head in project #{project_name} to <#{new_head}>."
     true
   end
+
+  def gc
+    $logger.info "Running git gc for <#{full_path}>."
+    cmd = %W(git --git-dir=#{full_path} gc)
+    system(*cmd)
+  end
 end