old_contents: from app import app
  from flask import redirect, render_template
  
  @app.route('/')
  def index():
      return render_template('index.html')
  
  # default 'catch all' route
  @app.route('/', defaults={'path': ''})
  @app.route('/<path:path>')
  def catch_all(path):
      return redirect('/')
  
new_contents: from app import app
  from app.models import Digit
  from flask import redirect, render_template, request, jsonify
  
  @app.route('/')
  def index():
      return render_template('index.html')
  
  # api route
  # parameters
  #
  # id: id to query, will return all otherwise
  # select: one value per item in the query
  # limit: limit, obviously.
  @app.route('/api')
  def api():
      query_id = request.args.get('id')  # get first id in query string
      query_limit = request.args.get('limit')  # get first limit in query string
      query_select = request.args.getlist('select')  # get all select params
  
      if query_id is not None:
          result = Digit.query.\
              filter(Digit.id == query_id).\
              all()
      else:
          result = Digit.query.limit(query_limit).all()
      return jsonify(result=[r.as_dict(query_select) for r in result])
  
  # default 'catch all' route
  @app.route('/', defaults={'path': ''})
  @app.route('/<path:path>')
  def catch_all(path):
      return redirect('/')
  
subject: Add basic functional DB /api route