Add more requirements to the package list

README.md

@@ -4,6 +4,8 @@ This is a central listing of all packages for
 [Nimble](https://github.com/nim-lang/nimble), a package manager for the
 [Nim programming language](http://nim-lang.org).
 
+NOTE: The packages listed here are not peer-reviewed or otherwise screened. We try to keep the list up-to-date but we cannot guarantee quality or maturity of the packages.
+
 ## Adding your own package
 To add your own package, fork this repository, edit
 [packages.json](packages.json) and make a pull request.
@@ -20,10 +22,16 @@ optional):
   * tags   - A list of tags describing this package.
   * description - A description of this package.
   * license - The license of the source code in the package.
-  * web    - An optional url for humans to read additional information about
+  * web    - An optional URL for humans to read additional information about
              the package.
+  * doc    - An optional URL for humans to read the package HTML documentation
 
-Your packages may be removed if the url stops working. It goes without saying
-that your pull request will not be accepted unless you fill out all of the
-above required fields correctly, the package that ``url`` points to must also
-contain a .nimble file, or else it will be rejected.
+### Requirements
+
+While we really appreciate your contribution, please ensure that you package matches the following requirements: other developers rely on your package. Non-compliant packages might be removed with no warning.
+
+* The URL should work, a .nimble file should be present and the package should be installable
+* The package should build correctly with the latest Nim release
+* The package should not contain files without a license or in breach of 3rd parties licensing
+* Non-mature packages should be flagged as such, especially if they perform security-critical tasks (e.g. encryption)
+* If abandoning a package, please tag it as "abandoned".