Re-add stack trace to detail view

Author: Greg Hatt

backend/schemas.py

@@ -95,7 +95,12 @@ class Meta:
     outputs = ma.List(ma.Nested(OutputTensorSchema()))
     inputs = ma.List(ma.Nested(InputTensorSchema()))
     arguments = ma.List(ma.Nested(OperationArgumentsSchema()))
+    stack_trace = ma.Method("get_stack_trace")
 
+    def get_stack_trace(self, obj):
+        if obj.stack_trace and len(obj.stack_trace):
+            return next(x for x in obj.stack_trace).stack_trace
+        return ""
 
 # Filesystem Schemas
 class RemoteConnectionSchema(ma.Schema):