Merged in feature/doc_import (pull request #177)

integration of background processor

* integration part 1

* feature working

* fix mimetype issue

internal/database/queries/batch.sql

@@ -71,4 +71,12 @@ WHERE batch_id = $1;
 -- name: CountDocumentsByBatchId :one
 SELECT COUNT(*) as count
 FROM documents 
-WHERE batch_id = $1;
+WHERE batch_id = $1;
+
+-- name: GetUnprocessedBatches :many
+SELECT id, client_id, original_filename, total_documents, 
+       processed_documents, failed_documents, invalid_type_documents,
+       status, progress_percent, created_at, completed_at
+FROM batch_uploads 
+WHERE status = 'processing'
+ORDER BY created_at ASC;