docs: update college discount information (#1140)

docs/use-cases/college.md

@@ -0,0 +1,34 @@
+# College Discount
+
+We have another potential transit discount use case, which is for students/faculty/staff from the Monterey-Salinas Transit (MST) area. We will be taking [the existing program](https://mst.org/fares/overview/) where students from certain schools ride free, expanding it to faculty and staff in some cases, and allowing those riders to enroll their contactless bank (credit/debit) cards for half-price (50%) discounts during fall and winter breaks.
+
+## Prototype
+
+Here's a clickable prototype showing the planned flow, having users enroll via their college's single sign-on (SSO) system:
+
+<iframe style="border: 1px solid rgba(0, 0, 0, 0.1);" width="500" height="900" src="https://www.figma.com/embed?embed_host=share&url=https%3A%2F%2Fwww.figma.com%2Fproto%2FSeSd3LaLd6WkbEYhmtKpO3%2FBenefits-(Identity-Verification-Login.gov)%3Fnode-id%3D7742%253A35091%26scaling%3Dscale-down%26page-id%3D7742%253A35066%26starting-point-node-id%3D7742%253A35091" allowfullscreen></iframe>
+
+## Process
+
+Here's what will happen behind the scenes in a success flow:
+
+```mermaid
+sequenceDiagram
+    actor rider
+    participant Benefits as Benefits app
+    participant IdG as Identity Gateway
+    participant SSO
+    participant Littlepay
+
+    rider->>Benefits: visits site
+    Benefits-->>IdG: redirected to sign in
+    IdG-->>SSO: redirected to sign in
+    rider->>SSO: enters credentials
+    SSO-->>IdG: user attributes
+    IdG-->>Benefits: user attributes
+    Benefits-->>Littlepay: enrollment start
+    rider->>Littlepay: enters payment card details
+    Littlepay-->>Benefits: enrollment complete
+```
+
+The plan is to determine whether the rider is eligible via SAML attributes and/or membership in a group on the college side.

mkdocs.yml

@@ -35,10 +35,11 @@ plugins:
   - awesome-pages
   - redirects:
       redirect_maps:
-        "students.md": "use-cases/students.md"
         "deployment/azure.md": "deployment/infrastructure.md"
         "getting-started/development.md": "development/README.md"
         "getting-started/docker-dynamic-ports.md": "development/docker-dynamic-ports.md"
+        "students.md": "use-cases/college.md"
+        "use-cases/students.md": "use-cases/college.md"
 
 extra_css:
   - https://use.fontawesome.com/releases/v5.13.0/css/all.css