Add logic for adding buttons for people

.pylintrc

         deprecated-sys-function,
         exception-escape,
         comprehension-escape,
-		too-few-public-methods
+		too-few-public-methods,
+		global-statement
 
 # Enable the message, report, category or checker with the given id(s). You can
 # either give multiple identifier separated by comma (,) or put this option

piket_client/gui.py

 # pylint: disable=E0611
 from PySide2.QtWidgets import (
     QApplication,
-    QPushButton,
     QGridLayout,
-    QWidget,
+    QInputDialog,
     QMainWindow,
+    QPushButton,
     QSizePolicy,
     QToolBar,
+    QWidget,
 )
 from PySide2.QtGui import QIcon
 from PySide2.QtCore import QSize
+
 # pylint: enable=E0611
 import requests
 
 
 
 def get_people() -> [dict]:
-    ''' Request list of active people from the server. '''
+    """ Request list of active people from the server. """
     request = requests.get(urljoin(SERVER_URL, "/people"))
     return request.json()["people"]
 
 
     @property
     def current_label(self) -> str:
-        ''' Return the label to show on the button. '''
+        """ Return the label to show on the button. """
         return f"{self.name} ({self.count})"
 
     def plop(self) -> None:
-        ''' Process a click on this button. '''
+        """ Process a click on this button. """
         req = requests.post(
             urljoin(SERVER_URL, f"people/{self.person_id}/add_consumption")
         )
 
 
 class NameButtons(QWidget):
-    ''' Main widget responsible for capturing presses and registering them.
-    '''
+    """ Main widget responsible for capturing presses and registering them.
+    """
+
     def __init__(self) -> None:
         super().__init__()
 
         self.init_ui()
 
     def init_ui(self) -> None:
-        ''' Initialize UI: build GridLayout, retrieve People and build a button
-        for each. '''
+        """ Initialize UI: build GridLayout, retrieve People and build a button
+        for each. """
         self.layout = QGridLayout()
 
         for index, person in enumerate(get_people()):
 
 
 class PiketMainWindow(QMainWindow):
-    ''' QMainWindow subclass responsible for showing the main application
-    window. '''
+    """ QMainWindow subclass responsible for showing the main application
+    window. """
+
     def __init__(self) -> None:
         super().__init__()
 
         self.init_ui()
 
     def init_ui(self) -> None:
-        ''' Initialize the UI: construct main widget and toolbar. '''
+        """ Initialize the UI: construct main widget and toolbar. """
         self.main_widget = NameButtons()
         self.setCentralWidget(self.main_widget)
 
         self.toolbar.setIconSize(QSize(icon_size, icon_size))
 
         # Left
-        self.toolbar.addAction(self.load_icon("add_person.svg"), "Nieuw persoon")
+        self.toolbar.addAction(
+            self.load_icon("add_person.svg"), "Nieuw persoon", self.add_person
+        )
         self.toolbar.addAction(self.load_icon("undo.svg"), "Heydrich")
 
         self.toolbar.addWidget(self.create_spacer())
         self.toolbar.addAction(self.load_icon("beer_bottle.svg"), "Bierrr")
         self.addToolBar(self.toolbar)
 
+    def add_person(self) -> None:
+        """ Ask for a new Person and register it, then rebuild the central
+        widget. """
+        name, ok = QInputDialog.getItem(
+            self,
+            "Persoon toevoegen",
+            "Voer de naam van de nieuwe persoon in, of kies uit de lijst.",
+            ["Cas", "Frenk"],
+            0,
+            True,
+        )
+        if ok and name:
+            req = requests.post(urljoin(SERVER_URL, "people"), json={"name": name})
+
+            self.main_widget = NameButtons()
+            self.setCentralWidget(self.main_widget)
+
     @staticmethod
     def create_spacer() -> QWidget:
         """ Return an empty QWidget that automatically expands. """
 
 
 def main() -> None:
-    ''' Main entry point of GUI client. '''
+    """ Main entry point of GUI client. """
     app = QApplication(sys.argv)
     font = app.font()
     size = font.pointSize()

piket_server/__init__.py

 def get_people():
     """ Return a list of currently known people. """
     people = [p for p in PEOPLE.values()]
+    people.sort(key=lambda p: p["name"])
     return jsonify(people=people)