feat(core): Add to markdown rendering model references

ref: #296 #308

docs/projects/centurion_erp/development/models.md

@@ -51,6 +51,7 @@ This section details the additional items that may need to be done when adding a
 
 - If the model is a primary model, add to model reference rendering in `app/core/lib/markdown_plugins/model_reference.py` function `tag_html`
 
+
 ## History
 
 Currently the adding of history to a model is a manual process. edit the file located at `core.views.history` and within `View.get_object` add the model to the `switch` statement.

docs/projects/centurion_erp/user/core/markdown.md

@@ -62,3 +62,22 @@ Available admonition types are:
 ## Ticket References
 
 Declare a ticket reference in format `#<ticket number>`, and it will be rendered as a link to the ticket. i.e. `#2`
+
+
+## Model
+
+A Model link is a reference to an item within the database. Supported model link items are:
+
+- cluster
+
+- config_group
+
+- device
+
+- service
+
+- software
+
+- operating system
+
+To declare a model link use syntax `$<type>-<model id>`. i.e. for device 1, it would be `$device-1`