How can I integrate teaching source code control (Git/Mercurial/etc) into my introductory CS class? In the words of Andrew Clay Shafer, “In software development, version control is the foundation of every other Agile technical practice.” (Allspaw &amp; Robbins, 2010).  Yet, 57% of CS curricula does not provide practical exposure to it. (Betz)

How can I teach the use of source code control as part of an introductory CS class?  

To put it another way: How can we introduce source code control early in the curriculum?
There are quite a few solutions which allow you to make a VCS part of your teaching.

For example, GitHub Classroom allows you to create assignments with some starter code, then invite your students to work on it and submit their changes through Git. They provide a promotional video here, which shows the workflow with it.

Scaffolding Version Control into the Computer Science Curriculum states:


  VCS and other professional tools are often introduced
  later in the educational curriculum, possibly in a software
  engineering course, generally a second-year or later course,
  and may not be reinforced through repetition and application
  in later classes. This is unfortunate, because powerful
  tools such as VCS can also be difficult for new users and
  especially those new to programming and software in general.
  The power and flexibility of new distributed VCS can
  make them especially challenging, unfriendly, and distracting
  for students already fully engaged in developing core
  competencies required in the computer science curriculum.


They propose GitSubmit as a helpful solution here, describing it as "A Custom Environment for Introducing
VCS to Novice Developers". Clearly, it's helpful here to introduce VCS as soon as possible, to avoid the issues described later in the paper, where higher level students have virtually no experience of using a VCS, despite its importance in industry.

For the pedagogical challenges, the presentation Challenges and Confusions in Learning Version
Control with Git seems interesting. They conclude:


  
  Introduce authentic/relevant use cases to motivate the use and
  learning of the system
  Authentic practical courses cause students to see the value of
  VCSs
  However, use VCSs throughout the curriculum, as, for instance,
  limited resources available during authentic project courses may
  limit how the system is adopted