add merge tag

To make it easier to identify merge models, we're experimenting with adding a `merge` tag for models created via a merge.

README.md

@@ -7,6 +7,7 @@ language:
 pipeline_tag: text-generation
 tags:
 - Math
+- merge
 ---
 
 ## Merged-AGI-7B
@@ -27,4 +28,4 @@ Detailed results can be found [Coming soon]()
 | MMLU (5-shot)         | Coming soon               |
 | TruthfulQA (0-shot)   | Coming soon               |
 | Winogrande (5-shot)   | Coming soon               |
-| GSM8K (5-shot)        | Coming soon               |
+| GSM8K (5-shot)        | Coming soon               |