Add description on how to translate appstore metadata to readme

ReadMe.md

@@ -36,6 +36,7 @@ Here you can read about further [support of the development](https://github.com/
 ### Translations
 
 We host and manage translations via [Weblate](https://hosted.weblate.org/engage/monal/).
+Appstore metadata can be translated as well: [Instructions Monal](appstore_metadata), [Instructions Quicksy](appstore_quicksy_metadata).
 
 [![Detailed translation status](https://hosted.weblate.org/widgets/monal/-/multi-auto.svg)](https://hosted.weblate.org/engage/monal/?utm_source=widget)
 

appstore_metadata/readme.md

@@ -0,0 +1,14 @@
+# Appstore metadata
+
+This directory contains the translations of the appstore metadata.
+
+## Changing translations already present
+Plese fork this repository, make your changes, commit them and then create a PR describing what you changed (andy why).
+
+# Adding new translations
+To add a new translation, please fork this repository, then create a new directory for your language.
+Copy over all files from `en-US` to this new directory and start translating them.
+Once you are done, commit your changes and submit a PR.
+
+**Important:** Only language codes [listed on this webpage](https://developermemos.com/posts/supported-ios-language-locale-codes-fastlane)
+or in the fastlane documentation are supported. We won't merge any PRs adding some language not on that list.

appstore_quicksy_metadata/readme.md

@@ -0,0 +1,14 @@
+# Appstore metadata
+
+This directory contains the translations of the appstore metadata.
+
+## Changing translations already present
+Plese fork this repository, make your changes, commit them and then create a PR describing what you changed (andy why).
+
+# Adding new translations
+To add a new translation, please fork this repository, then create a new directory for your language.
+Copy over all files from `en-US` to this new directory and start translating them.
+Once you are done, commit your changes and submit a PR.
+
+**Important:** Only language codes [listed on this webpage](https://developermemos.com/posts/supported-ios-language-locale-codes-fastlane)
+or in the fastlane documentation are supported. We won't merge any PRs adding some language not on that list.