revert to current_app.config at post_operation and DS Store gitignore

Author: shriram192

.gitignore

@@ -128,4 +128,7 @@ dmypy.json
 # Pyre type checker
 .pyre/
 
-.idea/
+.idea/
+
+#DS Store Mac OS
+.DS_Store

servicex_codegen/post_operation.py

@@ -36,7 +36,7 @@
 import zipfile
 from tempfile import TemporaryDirectory
 
-from flask import Response, request
+from flask import Response, current_app, request
 from flask_restful import Resource
 from requests_toolbelt import MultipartEncoder
 
@@ -93,7 +93,7 @@ def post(self):
                 zip_data = self.stream_generated_code(generated_code_result)
                 # code gen transformer returns the default transformer image mentioned in
                 # the config file
-                transformer_image = os.environ.get('TRANSFORMER_SCIENCE_IMAGE')
+                transformer_image = current_app.config.get('TRANSFORMER_SCIENCE_IMAGE')
 
                 # MultipartEncoder library takes multiple types of data fields and merge
                 # them into a multipart mime data type