Can someone explain what x = x.view(x.size(0), -1) does in this code?

class MyNet(nn.Module):

    def init(self): 

        super(MyNet, self).init()

        self.classifier = nn.Sequential(

            nn.Linear(784, 48),  # 28 x 28 = 784

            nn.ReLU(),

            nn.Linear(48, 24),

            nn.ReLU(),

            nn.Linear(24, 10)

        )

    def forward(self, x):

        x = x.view(x.size(0), -1)

        x = self.classifier(x)

        return x

I want to know what does this x.view(x.size(0), -1) do in this? And it is the MNIST dataset.