doc: add documentation for the new example

Author: cadenmyers13

docs/examples/README

@@ -159,3 +159,8 @@ future versions.
   recipes to be written with less code. This is not the same as a
   full-featured scripting interface, but rather somewhere in between a
   scripting interface and the API.
+
+- parallel_refinement.py\_
+  This demonstrates fitting the fcc nickel structure to measured PDF data,
+  and compares running several such refinements sequentially versus in
+  parallel using the multiprocessing module.

docs/source/examples.rst

@@ -27,6 +27,7 @@ Examples
 .. _nppdfsas.py: examples/nppdfsas.html
 .. _interface.py: examples/interface.html
 .. _simplerecipe.py: examples/simplerecipe.html
+.. _parallel_refinement.py: examples/parallel_refinement.html
 
 
 Files
@@ -54,3 +55,4 @@ Files
    examples/nppdfsas.rst
    examples/interface.rst
    examples/simplerecipe.rst
+   examples/parallel_refinement.rst

docs/source/examples/parallel_refinement.rst

@@ -0,0 +1,7 @@
+.. _parallel_refinement.py:
+
+========================
+parallel_refinement.py
+========================
+
+.. literalinclude:: ../../examples/parallel_refinement.py