Add a "for teachers" page which we can direct teachers to

- I would like a page to send to teachers, so that they can intgrate
  this into their courses.  This includes some sample text to say how
  it can be used.

- Review: does text make sense?

source/for-teachers.rst

@@ -0,0 +1,67 @@
+For teachers
+============
+
+If you are here, you are probably a teacher of some course that
+requires basic practical computational skills (Linux command line,
+git, shell scripting, etc), but you don't want to have to teach that
+yourself.  We have the solution for you here, which can be used in
+different ways:
+
+* Send your students here when it is clear they are missing some
+  prerequisites
+* Add this course as a soft prerequisite/recommended reading
+* You contribute new material here, instead of making your own
+  prerequisite documents.
+
+Our philosophy is "all the basics someone needs to know is online
+somewhere", so we help people find that rather than try to make our
+own material.  This also helps people become more self-sufficient in
+the future.
+
+
+
+Sample text
+-----------
+
+This could be added to your course prerequisites/syllabus, for
+example:
+
+
+    To succeed in this course, it is best to have some practical
+    skills in {Linux and command line work, lightweight software
+    development tools, ...}.
+    You can review this at https://handsonscicomp.readthedocs.io/.
+    For this course, the {C and D levels are important for success.
+    You should especially focus on C10 Basic shell, C23 Text editors
+    and IDEs, C20 Shell Scripting, and all D-level modules}.  Quickly
+    browsing and going back when you need more details is fine.
+
+
+
+What content should be added here?
+----------------------------------
+
+This site isn't about basic programming courses or the kinds of things
+you would teach in your courses.  It also isn't about writing our own
+new material - almost everything can be found online, somewhere.  We
+want to make that easy to find.  It also doesn't replace a dedicated
+course on these topics: this is more informal and just a starting
+point.
+
+It is likely that you will know of or find some **better
+videos/reading material than what we have currently linked**.  Please
+send that to us!  We have two categories, short video intro intros
+(hopefully with examples) and then longer reading, about an hour or
+so.
+
+**There may also be modules (topic + description + video + reading)
+which could be added.**  We will try to have some editorial judgment
+to keep the "main list" short, but we have an "extras" area for each
+level.
+
+To submit a proposal, please use the `GitHub repository
+<https://github.com/coderefinery/handsonscicomp>`__ if possible.  You
+can read more about directly modifying the source with pull requests
+on the `contributing page
+<https://github.com/coderefinery/handsonscicomp/blob/master/CONTRIBUTING.rst>`__.
+

source/index.rst

@@ -271,6 +271,7 @@ be interesting to you.
 
    about
    fitech-info
+   for-teachers
 
 .. toctree::
    :hidden: