Add wiki implementation of InnerSource portal pattern (#637)

Add wiki implementation of InnerSource portal pattern. To structure the information more clearly, this adds a new "Implementation" section to this pattern, which complements the "Solution" and "Known Instances" section.

Author: rrrutledge

patterns/2-structured/innersource-portal.md

@@ -52,10 +52,39 @@ Key properties of the portal are:
 
 When launching the portal, a communications campaign promoting the addition of InnerSource data files or meta-data to code repositories should be considered, to bolster the number of projects displayed within the portal.
 
+### Implementations
+
+#### SAP Project Portal
+
 A [reference implementation](https://github.com/SAP/project-portal-for-innersource) of an InnerSource portal is available on GitHub and open for contributions. It lists all InnerSource projects of an organization in an interactive and easy to use way. Projects can self-register using a dedicated GitHub topic and provide additional metadata.
 
 ![Example of an InnerSource Portal](../../assets/img/portal-overview.png "Example of an InnerSource Portal")
 
+#### Wiki
+
+As a simple way to start, you can set aside a page on an internal wiki for listing out available projects.
+An easy way to display this information is in a table with columns giving just a little bit of extra information about the projects.
+Try to have just enough columns so that viewers can determine if they want to learn more about the project, but no more.
+Too much information will make the page overwhelming and difficult to use.
+Individuals and teams can self-add their projects to the page.
+
+Here is a sample set of columns:
+
+* **Name**.  Name of the project (optionally linked to its homepage).
+* **Brief Description**.  Explaining the purpose of the project (which problem does it solve?)
+* **Technology Pre-requisites**.  You must use these technologies in order to on-board to the project.
+* **Getting Started**.  Link to instructions on how to start using the project.
+* **Chat**.  Link to a chat channel to ask questions about the project.
+* **Host Team**.  Seeing if a team is behind the project can help others to have the confidence to use it.
+* **Production Since**.  How long as the project been used in a production environment?  Seeing this information is a rough proxy for its maturity.
+* **Contribution**.  Link to instructions on how to contribute to the project.
+
+This solution doesn't allow for a fancy display - it is just a wiki table.
+If it's important for you to have a snazzy-looking UI, then this idea won't work for you.
+Additionally, if you end up with a lot of projects (e.g. nearing 100),
+this solution won't scale to allow the search and filtering or auto-updating of project entries that you'll probably need.
+It is a good solution for a portal with a few dozen projects, though.
+
 ## Resulting Context
 
 * The InnerSource Portal has enabled InnerSource project owners to advertise their projects to an organization-wide audience.  Due to this increased visibility they are attracting much larger communities of contributors than ever before.
@@ -78,6 +107,7 @@ A [reference implementation](https://github.com/SAP/project-portal-for-innersour
 * **Airbus** used the [SAP Portal](https://github.com/SAP/project-portal-for-innersource) as a Proof of Concept. It is now using the [Bazaar plugin](https://github.com/backstage/backstage/blob/master/plugins/bazaar/README.md) of [Backstage](https://backstage.io) as the latter became the official developer experience tool internally. It provides a convenient self-registering capability for all the divisions.
 * **Mercado Libre** use an instance of the [SAP portal](https://github.com/SAP/project-portal-for-innersource) to discover existing InnerSource projects within the organization.
 * **Mercedes-Benz** is [using](https://opensource.mercedes-benz.com/news/sponsor_innersource_commonsoss) the SAP reference implementation mentioned above for their InnerSource Portal.
+* **WellSky** has a simple _Confluence Wiki_ page were InnerSource and reusable projects are listed.
 
 ## References