commit messages could be a bit more specific (ie. updated user profile with working user image)
Would be nice to have a comments in code explaining what it does. I forget this as well, but something to keep in mind.
reading_list_controller has commented out code without any comments as to why it is commented out.
password_reset_controller has a LOT of very good comments, i assume they came with the gem? Might want to clean them up a bit to be more consistent with the rest of your code. Anyone looking at your code will definitely think that was gem generated comments.
Indentation and syntax is really consistent and well spaced. Good job!
A lot of migration files. I wonder if scraping your DB and rewriting your models might help clean up the list a bit. Seeing a lot of Add Columns, potential employers looking through the code could possibly view that as sloppy.
read me does not have any information
I see some styling in application.scss that could be in books.scss

Note: Great job with the time you had. Really like the idea and what you have so far.