modify readme

Author: dario-coscia

tutorials/README.md

@@ -6,7 +6,6 @@ In this folder we collect useful tutorials in order to understand the principles
 
 | Description   | Tutorial |
 |---------------|-----------|
-Introduction to PINA for Physics Informed Neural Networks training|[[.ipynb](tutorial1/tutorial.ipynb), [.py](tutorial1/tutorial.py), [.html](http://mathlab.github.io/PINA/_rst/tutorials/tutorial1/tutorial.html)]|
 How to build a `Problem` in PINA|[[.ipynb](tutorial16/tutorial.ipynb), [.py](tutorial16/tutorial.py), [.html](http://mathlab.github.io/PINA/_rst/tutorials/tutorial16/tutorial.html)]|
 Introduction to PINA `Equation` class|[[.ipynb](tutorial12/tutorial.ipynb), [.py](tutorial12/tutorial.py), [.html](http://mathlab.github.io/PINA/_rst/tutorials/tutorial12/tutorial.html)]|
 Building custom geometries with `DomainInterface` class|[[.ipynb](tutorial6/tutorial.ipynb), [.py](tutorial6/tutorial.py), [.html](http://mathlab.github.io/PINA/_rst/tutorials/tutorial6/tutorial.html)]|
@@ -15,6 +14,7 @@ PINA and PyTorch Lightning, training tips and visualizations|[[.ipynb](tutorial1
 ## Physics Informed Neural Networks
 | Description   | Tutorial  |
 |---------------|-----------|
+Introduction to Physics Informed Neural Networks training|[[.ipynb](tutorial1/tutorial.ipynb), [.py](tutorial1/tutorial.py), [.html](http://mathlab.github.io/PINA/_rst/tutorials/tutorial1/tutorial.html)]|
 Two dimensional Poisson problem using Extra Features Learning     |[[.ipynb](tutorial2/tutorial.ipynb), [.py](tutorial2/tutorial.py), [.html](http://mathlab.github.io/PINA/_rst/tutorials/tutorial2/tutorial.html)]|
 Two dimensional Wave problem with hard constraint |[[.ipynb](tutorial3/tutorial.ipynb), [.py](tutorial3/tutorial.py), [.html](http://mathlab.github.io/PINA/_rst/tutorials/tutorial3/tutorial.html)]|
 Resolution of a 2D Poisson inverse problem |[[.ipynb](tutorial7/tutorial.ipynb), [.py](tutorial7/tutorial.py), [.html](http://mathlab.github.io/PINA/_rst/tutorials/tutorial7/tutorial.html)]|