add unique constraint to Exploration\'s members
fix a typo
fix a boundary condition bug
fix a toast message
add RegistrationFormActivity
disabele checking CSRF token to enable a user registration...
fix saving bugs
add some columns for a exploration's state
fix to display a route name
add methods for processing a exploration
change to use a http client
change to use a http client
change to use a http client
add a button of fake taking image for debug
add a button of fake taking image for debug
add a finalizing process
fix a bug of null photo_uri