modularize src

+ merge main.py and manage.py
+ move start logic to swingmusic/__main__.py
+ add a run.py on the project root

swingmusic/crons/__init__.py

@@ -0,0 +1,31 @@
+import time
+import schedule
+
+from swingmusic.crons.mixes import Mixes
+from swingmusic.lib.recipes.recents import RecentlyAdded, RecentlyPlayed
+from swingmusic.lib.recipes.topstreamed import TopArtists
+from swingmusic.utils.threading import background
+
+
+@background
+def start_cron_jobs():
+    """
+    This is the function that triggers the cron jobs.
+    """
+    # NOTE: RecentlyPlayed is not a CRON job, it's triggered here to
+    # populate the values for the very first time.
+    RecentlyPlayed()
+    RecentlyAdded()
+
+    # Initialized CRON jobs
+    TopArtists()
+    TopArtists(duration="week")
+    Mixes()
+
+    # Trigger all CRON jobs when the app is started.
+    schedule.run_all()
+
+    # Run all CRON jobs on a loop.
+    while True:
+        schedule.run_pending()
+        time.sleep(1)