DL-197: Add DISCLAIMER file to the project

DISCLAIMER is missing for source release.

Author: Sijie Guo <sijie@apache.org>

Reviewers: Jia Zhai <zhaijia03@gmail.com>

Closes #125 from sijie/sijie/include_DISCLAIMER_file
diff --git a/DISCLAIMER b/DISCLAIMER
new file mode 100644
index 0000000..09fea68
--- /dev/null
+++ b/DISCLAIMER
@@ -0,0 +1,7 @@
+Apache DistributedLog is an effort undergoing incubation at The Apache Software Foundation (ASF),
+sponsored by the Apache Incubator PMC. Incubation is required of all newly accepted projects until
+a further review indicates that the infrastructure, communications, and decision making process have
+stabilized in a manner consistent with other successful ASF projects. While incubation status is not
+necessarily a reflection of the completeness or stability of the code, it does indicate that the
+project has yet to be fully endorsed by the ASF.
+