Summarise how we release the fixed version of SpotBugs (spotbugs#145)

* explain how we release the fixed version of SpotBugs

* update RELEASE_PROCEDURE.md to merge suggestions into its content

* explain how to release document

* update description about Eclipse Marketplace

* update description for Read the Docs

* explain how to generate old manual site

* add URL of download site for Saxon and docbook-xsl

RELEASE_PROCEDURE.md

@@ -0,0 +1,46 @@
+# Release procedure
+
+When you release fixed version of SpotBugs, please follow these procedures.
+
+## Release to Maven Central
+
+Add necessary properties to `~/.gradle/gradle.properties` and make sure that you have proper `eclipsePlugin/local.properties` file to release Eclipse plugin at the same time. Then run `./gradlew build smoketest uploadArchives`.
+
+Check [SonaType official page](http://central.sonatype.org/pages/gradle.html) for detail.
+
+## Release to Eclipse Update Site
+
+Send pull-request to spotbugs/spotbugs.github.io, to update contents.
+As files to upload, you can use the zip file which is uploaded to Maven Central when you release to there.
+
+See [this pull-request](https://github.com/spotbugs/spotbugs.github.io/pull/12) as example.
+
+## Release to Eclipse Marketplace
+
+No action necessary. Just push latest plugin to Eclipse Update Site then it's enough.
+If you need to update [entry at Eclipse Marketplace](https://marketplace.eclipse.org/content/spotbugs-eclipse-plugin), please contact with @KengoTODA or @iloveeclipse.
+
+## Release to Gradle Plugin Portal
+
+Add necessary properties to `~/.gradle/gradle.properties` and run `./gradlew publishPlugins`.
+
+## Release old manuals
+
+Send pull-request to spotbugs/spotbugs.github.io, to update contents.
+To generate files to upload, add following properties to `spotbugs/local.properties` and run `./gradlew ant-docs`, then you can get built contents at `spotbugs/build/doc`.
+
+```properties
+saxon.home=path/to/saxon6-5-5
+xsl.stylesheet.home=path/to/docbook-xsl-1.71.1
+```
+
+Use sourceforge to download [Saxon 6.5.5](https://sourceforge.net/projects/saxon/files/saxon6/6.5.5/) and [docbook-xsl 1.71.1](https://sourceforge.net/projects/docbook/files/docbook-xsl/1.71.1/).
+
+## Release to ReadTheDocs
+
+Install `docker 1.13.1` or later in your local, and make sure `docs/build.sh` can run without error. This script should generate HTML pages under `docs/.build/html`. If there is no problem, ReadTheDocs should be possible to build and publish documents to their site. Simply merge your change to `master` then it will be used by [the `latest` document](http://spotbugs.readthedocs.io/en/latest/).
+
+Note that we manage manuals by two ReadTheDocs projects: [spotbugs](https://readthedocs.org/projects/spotbugs/) and [spotbugs-ja](https://readthedocs.org/projects/spotbugs-ja/).  
+When we want to add active versions for documents, visit [version page](https://readthedocs.org/projects/spotbugs/versions/). When we want to add more languages, follow [official document](http://docs.readthedocs.io/en/latest/localization.html#project-with-multiple-translations) and create a new ReadTheDocs project for new language.
+
+If you need maintainer access to Read the Docs, please contact with @KengoTODA.

spotbugs/build.gradle

@@ -206,6 +206,10 @@ uploadArchives {
   }
 }
 
+ant.importBuild('build.xml') { antTargetName ->
+  'ant-' + antTargetName
+}
+
 // TODO : jsr305.jar (really?)
 // TODO : generatemanual (we should decide what to do with the manual)
 // TODO : generatepdfmanual