Fix text flow issue around screenshot (#570)

"You should see the following screen:" gets cut off at "You should see" with the screenshot in between, and "the following screen:" shown to the bottom left of this screenshot.

Adding an extra newline fixes the issue.

README.md

@@ -71,8 +71,10 @@ Try a browser refresh `cmd + r`.
 
 ## Loading sample data
 If you would like to load sample data, you can do so by navigating to **Load DB** under the Administration menu.  You should see the following screen:
+
 ![Load DB screenshot](screenshots/load-db.png)
 
+
 Click on ***Choose File*** and select the file **sample-data.txt** which is included in root directory of the repo at [sample-data.txt](sample-data.txt).
 Next, click on ***Load File***.  When the database load is complete a message will appear indicating if the load was successful.