Add a CLI-command to get quotes for securities in the database.

piecash claims to support that, but I haven't found out how.

See: https://flask.palletsprojects.com/en/2.0.x/cli/#custom-commands

Output of gnucash-web commodities update_prices on my uberspace on Wed, 28 Dec 2022 23:00:29 +0000:

New price for L4K3.DE: €[email protected] -> €[email protected]
Traceback (most recent call last):
  File "/home/joshua/gnucash_web/ENV/bin/gnucash-web", line 8, in <module>
    sys.exit(cli())
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/click/core.py", line 1128, in __call__
    return self.main(*args, **kwargs)
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/flask/cli.py", line 600, in main
    return super().main(*args, **kwargs)
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/click/core.py", line 1053, in main
    rv = self.invoke(ctx)
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/click/core.py", line 1659, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/click/core.py", line 1659, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/click/core.py", line 1395, in invoke
    return ctx.invoke(self.callback, **ctx.params)
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/click/decorators.py", line 26, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/flask/cli.py", line 444, in decorator
    return __ctx.invoke(f, *args, **kwargs)
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/click/core.py", line 754, in invoke
    return __callback(*args, **kwargs)
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/click/decorators.py", line 26, in new_func
    return f(get_current_context(), *args, **kwargs)
  File "/home/joshua/gnucash_web/ENV/lib64/python3.9/site-packages/gnucash_web/commodities.py", line 117, in update_prices
    f"Price for {commodity.menmonic}:"
AttributeError: 'Commodity' object has no attribute 'menmonic'

On one-handed touch devices such as smartphones, it is usually more ergonomic to have the navbar at the bottom of the screen, where the thumb usually rests.

This is also the default for the URL bar on Firefox for Android.

Possible solution ist to do the following below a certain Bootstrap breakpoint:

• Set navbar to class="fixed-bottom"
• Invert .scrolled-up and .scrolled-down CSS rules
• Remove top padding on body

Entering an expense (negative transaction value) could be more convenient, e.g. by having a "expense / income" checkbox or a small "invert" button.

We should add a quick explanation to the README on how to either create an empty book in an SQL database or how to migrate an existing GnuCash-XML-File into an SQL-server using the desktop client.