title: Developing a gem in parallel with another project
body: <p>Let's say your working on a product, and you realise that some of the code is general enough to be extracted out to a gem.</p>
  
  <p>So you create a new project, build the gem, publish it to Rubygems, and then reference it in your main project's Gemfile.</p>
  
  <p>Then you discover a small bug with how the gem interacts with your product. Each time your make a fix, building and installing the gem locally can take about 15 seconds. How do you minimise this to have a quick develop/test cycle?</p>
  
  <p>(Also it seems that the locally built gem's version number could contradict with what you've pushed to Rubygems, leading to confusion.)</p>
  
  <p>Any best practice guides on this subject?</p>