docs: Add Trivy migration guide (#1961)

docs/guides/trivy.md

@@ -0,0 +1,47 @@
+# Moving towards configuration scanning with Trivy
+Overtime we've taken [trivy][trivy] to be the go-to scanning tool for a vareity of things. This also includes terraform scanning.
+
+This section describes some differences between Trivy and tfsec.
+
+| Feature              | Trivy                                                  | tfsec                |
+|----------------------|--------------------------------------------------------|----------------------|
+| Policy Distribution | Embedded and Updated via Registry                      | Embedded             |
+| Custom Policies      | Rego                                                   | Rego, JSON, and YAML |
+| Supported Formats    | Dockerfile, JSON, YAML, Terraform, CloudFormation etc. | Terraform  Only      |
+
+
+# Comparison with examples
+## Simple scan
+### With Trivy
+```shell
+$ trivy config <dir>
+```
+### With tfsec
+```shell
+$ tfsec <dir>
+```
+
+## Passing tfvars
+### With Trivy
+```shell
+$ trivy --tf-vars <vars.tf> <dir>
+```
+### With tfsec
+```shell
+$ tfsec <dir> --tf-vars-file <vars.tf>
+```
+
+## Report formats
+### With Trivy
+```shell
+$ trivy config --format <format-type> <dir>
+```
+
+### With tfsec
+```shell
+$ tfsec <dir> --format <format-type>
+```
+
+We welcome any feedback if you find features that today are not available with Trivy misconfigration scanning that are available in tfsec. 
+
+[trivy]: https://github.com/aquasecurity/trivy

mkdocs.yml

@@ -25,6 +25,7 @@ theme:
 nav:
 - HOME: index.md
 - Guides:
+  - Migration: guides/trivy.md
   - Installation: guides/installation.md
   - Signature Verification: guides/signing.md
   - Quick Start: guides/quickstart.md