Support auracle as an update backend (#669)

i3pystatus/updates/auracle.py

@@ -0,0 +1,24 @@
+from i3pystatus.core.command import run_through_shell
+from i3pystatus.updates import Backend
+
+
+class Auracle(Backend):
+    """
+    Checks for updates in Arch User Repositories using the `auracle` AUR helper.
+
+    Depends on auracle AUR agent - https://github.com/falconindy/auracle
+    """
+
+    @property
+    def updates(self):
+        command = ["auracle", "sync"]
+        auracle = run_through_shell(command)
+        return auracle.out.count('\n'), auracle.out
+
+Backend = Auracle
+
+if __name__ == "__main__":
+    """
+    Call this module directly; Print the update count and notification body.
+    """
+    print("Updates: {}\n\n{}".format(*Backend().updates))