run rake task inside rails application

Hi all,

I want to run asset precompile task inside the rails application,As I had many dependencies who will change the code,in that case all the time whenever they change i need to run the script as I cant give server access to them
so I am providing the GUI for them from that they alone can run the script,so,I have built UI to run the task with some parameter like

     system("Template='#{params[:template]}' Theme='#{params[:theme]}' rake assets:precompile)

I am getting two values from UI(params[:template],params[:theme]).Another thing i want to run this task in another path(site path) means Admin side UI is there that task should execute in Site directory,

 Dir.chdir "#{SITEPATH}" do
     `Template="small_business_1" Theme="1" rake assets:precompile`
      # system("Template='small_business_1' Theme='1' rake assets:precompile)

I have tried this code by putting in controller and lib, but this is not working.

I have tried with shell script also.

Could please anyone can help me.