Adding new context method local_md5 for v1.4

website/docs/reference/dbt-jinja-functions/local-md5.md

@@ -0,0 +1,18 @@
+---
+title: "local_md5"
+id: "local_md5"
+---
+
+The `local_md5` context variable calculates an [MD5 hash](https://en.wikipedia.org/wiki/MD5) of the given string. It's called `local_md5` to emphasize that the hash is calculated _locally_, in the dbt-Jinja context. This function is intended for generally advanced use cases: generating unique identifiers within custom materialization or operational logic, such as to avoid collisions between temporary relations, or to identify changes by comparing checksums.
+
+It should not be confused with the `md5` SQL function, supported by many SQL dialects, which runs remotely in the data platform. You should always use SQL hashing functions when generating <Term id="surrogate-key">surrogate keys</Term>.
+
+Usage:
+```sql
+-- source
+{%- set value_hash = local_md5("hello world") -%}
+'{{ value_hash }}'
+
+-- compiled
+'5eb63bbbe01eeed093cb22bb8f5acdc3'
+```