put readme cross-reference

transforms/universal/doc_id/Readme.md

@@ -18,6 +18,10 @@ is unique across all rows in all tables provided to the `transform()` method.
 To enable this annotation, set `int_id_column` to the name of the column, where you want 
 to store it. 
 
+Document IDs are generally useful for tracking annotations to specific documents. Additionally 
+[fuzzy deduping](../fdedup) relies on integer IDs to be present. If your dataset does not have
+document ID column(s), you can use this transform to create ones.
+
 ## Building
 
 A [docker file](Dockerfile) that can be used for building docker image. You can use

transforms/universal/fdedup/Readme.md

@@ -114,6 +114,9 @@ Above you see both parameters and their values for small runs (tens of files). W
 
 ## Running
 
+In order to run this transform, you need to have an integer doc id in every row of data. [Test data](test-data/input)
+ALready has this column, but if you run on our own dataset, please use [doc_id transform](../doc_id) to create one.
+
 We also provide several demos of the transform usage for different data storage options, including
 [local file system](src/fdedup_local_ray.py) and [s3](src/fdedup_s3_ray.py)