Add assign

src/tools/miri/triagebot.toml

@@ -10,5 +10,14 @@ allow-unauthenticated = [
 # Gives us the commands 'ready', 'author', 'blocked'
 [shortcut]
 
+# Gives us 'claim', 'release-assignment', 'assign @user'
+[assign]
+# If set, posts a warning message if the PR is opened against a non-default
+# branch (usually main or master).
+warn_non_default_branch = true
+# If set, the welcome message to new contributors will include this link to
+# a contributing guide.
+contributing_url = "https://rustc-dev-guide.rust-lang.org/contributing.html"
+
 [no-merges]
 exclude_titles = ["Rustup"]