add file and folder_zip svg icons

apps/backend/app/models/experience_link.py

@@ -16,22 +16,23 @@ class ExperienceLink(Base):
     id = Column(
         Integer,
         primary_key=True,
-        index=True
+        index=True,
+        nullable=False
     )
 
     label = Column(
         String(255),
-        nullable=False
+        nullable=True
     )
 
     link = Column(
         String(255),
-        nullable=False
+        nullable=True
     )
 
     icon_path = Column(
         String(255),
-        nullable=False
+        nullable=True
     )
 
     experience_id = Column(