Set STATIC_ROOT to a filesystem directory. (see #673)

The issue shows a message that talks about not setting
STATIC_ROOT to a filesystem directory, and how that is
the cause of a problem. The current configuration appears,
by setting its path to an empty string, to have /static/
appear at the root of the app directory. So, this change
attempts to keep that as it is, but express it differently
by specifying the current directory instead.

gobotany/settings.py

@@ -212,7 +212,7 @@
 
 # Static files (CSS, JavaScript, images)
 # https://docs.djangoproject.com/en/1.11/howto/static-files/
-STATIC_ROOT = ''
+STATIC_ROOT = (THIS_DIRECTORY)
 STATIC_URL = '/static/'
 STATICFILES_DIRS = (
     os.path.join(THIS_DIRECTORY, 'static'),