add hemdall install

Change-Id: I153cb95fd78eeca382814ddd28b738c65a2bb0bf
diff --git a/_samsung/samsunggalaxya31.markdown b/_samsung/samsunggalaxya31.markdown
index 5ece827..0ab628c 100755
--- a/_samsung/samsunggalaxya31.markdown
+++ b/_samsung/samsunggalaxya31.markdown
@@ -30,4 +30,6 @@
 
 {% include odininstall.html %}
 
+{% include heimdallinstall.html %}
+
 {% include ddinstall.html %}