title: How to manage multiple spiders in a scrapy project
body: <p>I am new to scrapy but have successfully created a fairly sophisticated spider. Now I want to add a few more to the same project. I tried copying my working spider and editing it to work with another target but I am getting all sorts of global variable errors. I have tried "scrapy crawl my_new_spider" but is seems that all spiders are being initiated. What gives? Should just add a new class in the existing spider? This doesn't seem scalable... any pointers would be appreciated. The docs got me pretty far but I am stumbling now.</p>
  
  <p>Many thanks!</p>