Copied over SWAssistant and CDR backend

Started converting them to new backend

internal/cdr/README.md

@@ -0,0 +1,44 @@
+# cdr-backend
+
+Stupid backend for [CDR]("https://github.com/CalebQ42/CustomDiceRoller").
+
+## APIs
+
+### Dice
+
+Dice sharing
+
+> POST: /upload?key={api_key}
+
+Upload a die.
+
+Request Body:
+
+```json
+{
+    // Die data
+}
+```
+
+Note: Only allows up to 1MB of data. If over 1MB returns 413. Further limits might be imposed in the future.
+
+Response:
+
+```json
+{
+    "id": "die ID",
+    "expiration": 0 // Unix time (Seconds) of expiration
+}
+```
+
+> GET: /die/{die id}?key={api_key}
+
+Get an uploaded die.
+
+Response:
+
+```json
+{
+    // die data minus uid
+}
+```