Add releasetools_test to TEST_MAPPING

Test: treehugger
Change-Id: I3a0f9e9e5dd8d49c22f466aa0605768fee3f4821
diff --git a/tools/releasetools/TEST_MAPPING b/tools/releasetools/TEST_MAPPING
new file mode 100644
index 0000000..3d57960
--- /dev/null
+++ b/tools/releasetools/TEST_MAPPING
@@ -0,0 +1,8 @@
+{
+    "presubmit": [
+        {
+            "name": "releasetools_test",
+            "host" : true
+        }
+    ]
+}