Fix warning on rails routes CONTROLLER=

Author: tpope

autoload/rails.vim

@@ -1676,6 +1676,7 @@ function! s:Rails(bang, count, arg) abort
   elseif rails#buffer().name() =~# '^\%(app\|config\|db\|lib\|log\|README\|Rakefile\|test\|spec\|features\)'
     let str = rails#buffer().default_rake_task(a:count)
     let str = s:gsub(str, '<TEST\w*\=', '')
+    let str = s:gsub(str, '<CONTROLLER\=', '-c ')
     if str ==# '--tasks'
       let str = ''
     else