I141 document login bug (#142)

* Created known issues section in developer docs

* Added known_issues page to documentation

* Documented the login failure bug

mkdocs/docs/developer/known_issues.md

@@ -0,0 +1,32 @@
+# Known Issues
+
+This section is for documenting known bugs developers may encounter and any temporary workarounds found.
+
+## Can't log in after deleting user records from database
+
+### Error message in terminal
+```
+server_1  | error: NotFound: No record found for id '6110af36a195d000504258e4'
+server_1  |     at new NotFound (/app_code/node_modules/@feathersjs/errors/lib/index.js:114:17)
+server_1  |     at /app_code/node_modules/feathers-mongoose/lib/service.js:147:17
+server_1  |     at processTicksAndRejections (internal/process/task_queues.js:97:5)
+```
+
+### Workaround
+Clear your browser's local storage for the IndEAA site.
+Guide on how to do this:
+[Google Chrome](https://superuser.com/questions/519628/clear-html5-local-storage-on-a-specific-page), [Firefox](https://stackoverflow.com/questions/6084099/how-to-view-delete-local-storage-in-firefox)
+
+You can also use the site in a private browser session for a temporary fix.
+
+### Causes
+When working with IndEAA it's possible to delete a user's account from the database while they are logged in (e.g. using a tool such as Mongodb Compass).
+
+
+When this user is logged out they will experience this bug.
+
+
+The user's session stores their account's `_id` field in local storage (even when logged out).   
+When a user attempts to log in with a given Google account, the browser will report the `_id` field which was in local storage. However, because the account was deleted from the database, the `_id` field will find no matches. This causes the error listed above.
+
+### 

mkdocs/mkdocs.yml

@@ -106,6 +106,7 @@ nav:
   - Coding Standards: developer/coding_standards.md
   - Data Engineering: developer/data_engineering.md
   - Database Support Scripts: developer/database_support_scripts.md
+  - Known Issues: developer/known_issues.md
   - Frontend:
     - Component vs Page: developer/frontend/component_vs_page.md
     - Transport/Integration Layer (Feathers-redux): developer/frontend/feathers_redux.md