Better document how-to-contribute part

[ekatef]

It would be very handy to have:

• explanation on how to make PR, the hand-on notebook from pypsa-earth hackaton can be used for this;
• add some ready-to-use git spells for the most frequent use cases (like definition of remotes, making a PR upon an existing PR)

[ekatef]

As discussed with @tacwebservices and @asolavi, it could make sense to add a brief explanation on the ideal contribution workflow, in particular on using branches to avoid merge conflicts when collaborating

[asolavi]

As discussed with @tacwebservices and @asolavi, it could make sense to add a brief explanation on the ideal contribution workflow, in particular on using branches to avoid merge conflicts when collaborating

Good point, @ekatef. @tacwebservices and I can share our experience once we've tried it and collaborate in the points you are making.

[ekatef]

As discussed with @tacwebservices and @asolavi, it could make sense to add a brief explanation on the ideal contribution workflow, in particular on using branches to avoid merge conflicts when collaborating

Good point, @ekatef. @tacwebservices and I can share our experience once we've tried it and collaborate in the points you are making.

@asolavi it would be very helpful! Looking forward for comments from you and @tacwebservices :)