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/entry.py

@@ -0,0 +1,18 @@
+from sqlalchemy import Column, Integer, String, ForeignKey
+from sqlalchemy.orm import relationship
+
+from pilgrim.models.photo_in_entry import photo_entry_association
+from ..database import Base
+
+
+class Entry(Base):
+    __tablename__ = "Entry"
+    id = Column(Integer, primary_key=True)
+    title = Column(String)
+    text = Column(String)
+    date = Column(String)
+    photos = relationship(
+        "Photo",
+        secondary=photo_entry_association,
+        back_populates="entries")
+    fk_TravelDiary_id = Column(Integer, ForeignKey("TravelDiary.id"))