docs: def drop_db():
      " Drop all tables. "
  
      from ..ext import db
  
      if prompt_bool("Are you sure? You will lose all your data!"):
          db.drop_all()
  
          # Evolution support
          from flask import current_app
          from flaskext.evolution import db as evolution_db
          evolution_db.init_app(current_app)
          evolution_db.drop_all()
  
          print "Database clearing"