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/models/travel_diary.py

@@ -0,0 +1,8 @@
+from sqlalchemy import Column, String, Integer
+
+from ..database import Base
+
+class TravelDiary(Base):
+    __tablename__ = "TravelDiary"
+    id = Column(Integer, primary_key=True)
+    name = Column(String)