Importing lessons on Git

00-intro.md

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+Introducing Version Control
+===========================
+
+Wolfman and Dracula have been hired by Universal Missions
+(a space services spinoff from Euphoric State University)
+to figure out where the company should send its next planetary lander.
+They want to be able to work on the plans at the same time,
+but they have run into problems doing this in the past.
+If they take turns,
+each one will spend a lot of time waiting for the other to finish.
+On the other hand,
+if they work on their own copies and email changes back and forth
+they know that things will be lost, overwritten, or duplicated.
+
+The right solution is to use [version control](../gloss.html#version-control)
+to manage their work.
+Version control is better than mailing files back and forth because:
+
+*   It's hard (but not impossible) to accidentally overlook or overwrite someone's changes,
+    because the version control system highlights them automatically.
+*   It keeps a record of who made what changes when,
+    so that if people have questions later on,
+    they know who to ask
+    (or blame).
+*   Nothing that is committed to version control is ever lost.
+    This means it can be used like the "undo" feature in an editor,
+    and since all old versions of files are saved
+    it's always possible to go back in time to see exactly who wrote what on a particular day,
+    or what version of a program was used to generate a particular set of results.
+
+This lesson shows how to use
+a popular open source version control system called Git.
+It is more complex than some alternatives,
+but it is widely used,
+primarily because of a hosting site called [GitHub](http://github.com).
+No matter which version control system you use,
+the most important thing to learn is not the details of their more obscure commands,
+but the workflow that they encourage.