Merge pull request #1504 from caskroom/readme-acceptable

readme: add acceptable casks

README.md

@@ -17,5 +17,24 @@ You can now install alternate versions of Casks.
 $ brew cask install iterm2-beta
 ```
 
+## Acceptable Casks
+
+**Please note that `caskroom/versions` is currently in the process of major changes in what we support, how long for and on what basis. For that reason, we may be harder on refusals for the near future.**
+
+[Similarly to `homebrew-versions`](https://github.com/Homebrew/homebrew-versions#acceptable-formulae), `caskroom/versions` is not intended to be used for all and any old versions you personally require for xyz project; casks submitted here should be expected to be used by a reasonable number of people and supported by contributors long-term.
+
+You may wish to consider hosting your own [tap](https://github.com/Homebrew/homebrew/blob/master/share/doc/homebrew/How-to-Create-and-Maintain-a-Tap.md) for casks you wish to personally support that do not meet the above standards.
+
+For this repo, rules for consideration are (following our [nomenclature](https://github.com/caskroom/homebrew-cask/blob/master/CONTRIBUTING.md#finding-a-home-for-your-cask)):
+
++ Include the latest minor version of legacy versions of commercial and freemium software.
++ Legacy versions of commercial and freemium software are restricted to a maximum of five casks.
++ Include beta, development, unstable, nightly, early access program, ….
++ Include language and regional versions other than US english of casks already in [the main repo](https://github.com/caskroom/homebrew-versions).
++ Include alternate versions of casks already in the main repo (developer editions, community editions, pro versions).
++ Refuse legacy versions of gratis or open-source software, unless there is a clear demonstrable need for them.
++ Legacy versions of gratis or open-source software that were accepted should be removed after one year.
++ Include casks that do not fit the rules, but need to exist somewhere since they are required by other casks.
+
 ## License
 Code is under the [BSD 2 Clause (NetBSD) license](https://github.com/caskroom/homebrew-versions/blob/master/LICENSE)