Fit the following data into a linear regression model.
x = [1, 2, 3, 4], y = [2, 4, 6, 8].
The linear regression model is y = 2x.
<sys>[INST] Fit the following data into a linear regression model. [/INST] Input:
x = [1, 2, 3, 4], y = [2, 4, 6, 8]. </sys>