Changed the names of the files to conform the python convection and also added photo_in_entry.py to diminish the cyclic import error in pylint

src/pilgrim/__init__.py

@@ -0,0 +1,8 @@
+from pilgrim.application import Application
+from pilgrim.command import main
+from pilgrim.database import Database, Base
+from pilgrim.models.travel_diary import TravelDiary
+from pilgrim.models.entry import Entry
+from pilgrim.models.photo import Photo
+
+__all__ = ["Application", "Database", "TravelDiary", "Entry", "Photo", "main", "Base"]