Add description of Risk Redux control_freak project. (#1104)

docs/content/tools/_index.md

@@ -37,4 +37,5 @@ See the [NIST Software Disclaimer](https://www.nist.gov/disclaimer) for more inf
 | [XSLT Tooling](https://github.com/usnistgov/oscal-tools/tree/master/xslt) | NIST OSCAL Project | A variety of Extensible Stylesheet Language (XSL) Transformations (XSLT), Cascading Style Sheets (CSS), and related utilities for authoring, converting, and publishing OSCAL content in various forms. | open source |
 | [XML Jelly Sandwich](https://github.com/wendellpiez/XMLjellysandwich) | Wendell Piez (NIST) | Interactive XSLT in the browser includes [OSCAL demonstrations](https://wendellpiez.github.io/XMLjellysandwich/oscal/). | open source |
 | [Xacta 360](https://www.telos.com/offerings/xacta-360-continuous-compliance-assessment/) | Telos | Xacta 360 is a cyber risk management and compliance analytics platform that enables users to create and submit FedRAMP system security plans (SSPs) in OSCAL format. Future OSCAL capabilities are forthcoming as the standard evolves. | [license](https://cdn.telos.com/wp-content/uploads/2021/06/22150746/Xacta-360-EULA-US.pdf) |
-| [Atlasity: Continuous Compliance Automation](https://atlasity.io/partnership/) | C2 Labs | Atlasity CE (release 2.0) runs in any environment and supports the development of OSCAL v1.0 content for Catalogs, Profiles, System Security Plans and Components. Additional detail can be found in this blog post: [Atlasity Delivers Free Tools to Create OSCAL Content](https://www.c2labs.com/post/atlasity-delivers-free-tools-to-create-oscal-content). | community edition |
+| [Atlasity: Continuous Compliance Automation](https://atlasity.io/partnership/) | C2 Labs | Atlasity CE (release 2.0) runs in any environment and supports the development of OSCAL v1.0 content for Catalogs, Profiles, System Security Plans and Components. Additional detail can be found in this blog post: [Atlasity Delivers Free Tools to Create OSCAL Content](https://www.c2labs.com/post/atlasity-delivers-free-tools-to-create-oscal-content). | community edition |
+| [control_freak](https://controlfreak.risk-redux.io/) | Risk Redux | This tool seeks to provide folks with a searchable and easy-to-navigate reference for NIST SP 800-53 Revision 5. It is [an open-source application from the Risk Redux project](https://github.com/risk-redux/control_freak), built using parsed content directly from the OSCAL repositories. | open-source |