from tkinter import *

def __init__(self):
    self.root = Tk()
    self.width = 800
    self.height = 400
    self.root.geometry("{}x{}".format(self.width, self.height))
    self.root.resizable(False, False)
    self.menu_bar()
    self.tool_bar()
    self.name = Label(self.root, text="Tester", bg="black", fg="white")

    self.root.mainloop()

def menu_bar(self):
    self.menu = Menu(self.root)
    self.root.config(menu=self.menu)
    self.subMenu = Menu(self.menu)
    self.menu.add_cascade(label="File", menu=self.subMenu)
    self.subMenu.add_command(label="New Project...")
    self.subMenu.add_command(label="Properties")
    self.subMenu.add_separator()
    self.subMenu.add_command(label="Do nothing")

def tool_bar(self):
    self.toolbar = Frame(self.root, bg="#555555")
    self.insert_button = Button(self.toolbar, text="Insert", bg="#555555", fg="white", activeforeground="white",
                                activebackground="#008CBA", borderwidth=0)
    self.insert_button.grid(row=0, column=0)

    self.print_buttom = Button(self.toolbar, text="Print", bg="#555555", fg="white", activeforeground="white",
                               activebackground="#008CBA", borderwidth=0,
                               command=self.root.quit)
    self.print_buttom.grid(row=0, column=1)
    self.toolbar.grid(row=0, column=0, sticky=EW)


if __name__ == '__main__':
    App()

class App:

    def __init__(self):
        self.root = Tk()
        ...
        self.root.columnconfigure(0,weight=1)
        ...