BURs: add processing and failed states.

When a BUR is approved, put it in a `processing` state. After it
successfully finishes processing, put it in the `approved` state. If it
fails processing, put it in the `failed` state.

If approving the BUR fails with a validation error, for example because
the alias already exists or an implication lacks a wiki, then leave the
BUR in the `pending` state. The `failed` state is only for unexpected
errors during processing.

app/logical/bulk_update_request_processor.rb

@@ -171,6 +171,11 @@ class BulkUpdateRequestProcessor
         raise Error, "Unknown command: #{command}"
       end
     end
+
+    bulk_update_request.update!(status: "approved")
+  rescue StandardError
+    bulk_update_request.update!(status: "failed")
+    raise
   end
 
   # The list of tags in the script. Used for search BURs by tag.

app/logical/d_text.rb

@@ -146,12 +146,19 @@ class DText
         embedded_script = "[expand]#{obj.processor.to_dtext}[/expand]"
       end
 
-      if obj.is_approved?
+      case obj.status
+      when "approved"
         "The \"bulk update request ##{obj.id}\":#{Routes.bulk_update_request_path(obj)} has been approved by <@#{obj.approver.name}>.\n\n#{embedded_script}"
-      elsif obj.is_pending?
+      when "pending"
         "The \"bulk update request ##{obj.id}\":#{Routes.bulk_update_request_path(obj)} is pending approval.\n\n#{embedded_script}"
-      elsif obj.is_rejected?
+      when "rejected"
         "The \"bulk update request ##{obj.id}\":#{Routes.bulk_update_request_path(obj)} has been rejected.\n\n#{embedded_script}"
+      when "processing"
+        "The \"bulk update request ##{obj.id}\":#{Routes.bulk_update_request_path(obj)} is being processed.\n\n#{embedded_script}"
+      when "failed"
+        "The \"bulk update request ##{obj.id}\":#{Routes.bulk_update_request_path(obj)} has failed.\n\n#{embedded_script}"
+      else
+        raise ArgumentError, "unknown bulk update request status"
       end
     end
   end