Added directory structure for gitbook

Author: adamblanchard

SUMMARY.md

@@ -106,6 +106,14 @@
 - [Backend](courses/backend/README.md)
   - [Advanced JavaScript](courses/backend/advanced-javascript/README.md)
   - [Databases](courses/backend/databases/README.md)
+    - [Week 1](courses/backend/databases/week1/README.md)
+      - [Preparation](courses/backend/databases/week1/preparation.md)
+      - [Session Plan](courses/backend/databases/week1/session-plan.md)
+      - [Assignment](courses/backend/databases/week1/assignment.md)
+    - [Week 2](courses/backend/databases/week2/README.md)
+      - [Preparation](courses/backend/databases/week2/preparation.md)
+      - [Session Plan](courses/backend/databases/week2/session-plan.md)
+      - [Assignment](courses/backend/databases/week2/assignment.md)
   - [Node](courses/backend/node/README.md)
   - [Final Backend Project](courses/backend/final-project/README.md)