Include markdown files in source assembly

Change-Id: Iadb5074d0e0d4fb2b7d4303aa405e9fc91f44ac6
Reviewed-on: https://asterix-gerrit.ics.uci.edu/429
Reviewed-by: Ian Maxon <imaxon@apache.org>
Reviewed-by: Till Westmann <tillw@apache.org>
Tested-by: Jenkins <jenkins@fulliautomatix.ics.uci.edu>
diff --git a/src/main/assembly/source.xml b/src/main/assembly/source.xml
index 024e742..3dc6d96 100644
--- a/src/main/assembly/source.xml
+++ b/src/main/assembly/source.xml
@@ -53,6 +53,7 @@
         <include>**/*.txt</include>
         <include>**/part-*</include>
         <include>**/*.cleaned</include>
+        <include>**/*.md</include>
       </includes>
       <excludes>
         <exclude>**/${project.build.directory}/**</exclude>