Add index for "name" field in role table

gns3server/db/models/roles.py

@@ -38,7 +38,7 @@ class Role(BaseTable):
     __tablename__ = "roles"
 
     role_id = Column(GUID, primary_key=True, default=generate_uuid)
-    name = Column(String, unique=True)
+    name = Column(String, unique=True, index=True)
     description = Column(String)
     is_builtin = Column(Boolean, default=False)
     permissions = relationship("Permission", secondary=permission_role_link, back_populates="roles")