Add new guidelines for PRs

Author: thibmaek

CONTRIBUTING.md

@@ -1,7 +1,7 @@
 # Contribution Guidelines
 > The pull request should have a useful title. Pull requests with `Update readme.md` as title will be closed right away. Please make sure you checked every box in the PR template.
 
-## Adding an item to the list
+## Before adding something to the list
 1. Make sure you are editing README.md only, no other files are allowed to be edited.
 2. Add your item to the category it belongs to. Try to avoid creating completely new categories.
 3. Make sure your item is added to the bottom of the items listed in a category, don't add it in at the middle.
@@ -10,7 +10,7 @@
 6. If there is only support for some devices please mention that by using the [badges](/media/badges) provided.
 7. Add something that is truly awesome and stands out. A project that shows how to monitor a greenhouse, water a plant or trigger LEDs are already out there on the web. This is not the place for those.
 
-### Adding to the list
+### Adding an item to the list
 1. Click README.md
 2. Click the *pencil button* in the upper right corner next to raw | blame | history
 3. Github will automatically create a fork for this repo on your account.
@@ -19,6 +19,8 @@
 6. You'll be taken to the PR screen, click the *Create Pull Request* button
 7. Make sure you check the boxes (and actually make sure they're right) and click *Create Pull Request*
 
+Submitted PRs will be checked as soon as possible. If something is incorrect it will be labeled `awaiting-user` with the problem stated in the PR comments. If a PR becomes stale or no action is taken after some time with the PR being labeled `awaiting-user`, this PR will get the `reply-timeout` label and will be closed.
+
 #### Gitmoji
 It's recommended that you use [gitmoji](https://gitmoji.carloscuesta.me/) when contributing. The supported gitmoji must proceed the commit message followed by a space and be one of: