chore: add disclaimer (#129)

Co-authored-by: tison <wander4096@gmail.com>

.asf.yaml

@@ -18,7 +18,7 @@
 # For more information, see https://cwiki.apache.org/confluence/display/INFRA/Git+-+.asf.yaml+features.
 
 github:
-  description: HoraeDB Website.
+  description: Apache HoraeDB (incubating) Website.
   homepage: https://horaedb.apache.org/
   labels:
     - rust

DISCLAIMER

@@ -0,0 +1,10 @@
+Apache HoraeDB (incubating) 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.

README.md

@@ -1,16 +1,12 @@
-## HoraeDB Documentation
-
-Welcome to HoraeDB documentation!
+## Apache HoraeDB (incubating) Website
 
 This repository stores all the source files of [HoraeDB docs website](https://apache.github.io/incubator-horaedb-docs/), the website is generated with [mdbook](https://rust-lang.github.io/mdBook/).
 
 **All files are written in standard markdown.**
 
 ## Contributing
 
-We very much welcome any contributions from the community to make HoraeDB documentation better.
-
-You can
+Welcome any contributions from the community. You can
 
 - Open an [issue](https://github.com/apache/incubator-horaedb-docs/issues) with any suggestions, or
-- Submit a [pull request](https://github.com/apache/incubator-horaedb-docs/pulls) to fix errors.
+- Submit a [pull request](https://github.com/apache/incubator-horaedb-docs/pulls) to improve the website (trivial fixes are welcome).