Add alternate and faster method for local clone

It can be used from normal local repositories, but not with "shallow"
clones (typically used in CI to save from retrieving the whole
history).

script/sequel-model-lines.rb

@@ -19,6 +19,10 @@ CHECKOUT_TEMP_DIR = '/tmp/sequel-loc'
 begin
   # Use a fresh clone
   system "git clone https://github.com/CartoDB/cartodb.git #{CHECKOUT_TEMP_DIR}"
+  # Here's how to use the local repo instead of cloning through network
+  #src_dir = `git rev-parse --show-toplevel`.strip
+  #system "git clone #{src_dir} #{CHECKOUT_TEMP_DIR}"
+
   Dir.chdir(CHECKOUT_TEMP_DIR) do
 
     CSV.open(OUTPUT_FILE, 'w') do |csv|