Create an introduction and a list of materials

[danilopedraza]

• [x] Establish a scheme for the instructions in README
  • [x] Create an introduction
  • [x] Create a list of materials
  • [x] Create a scheme of the OS installation process
  • [x] Create a scheme of the SSH connection
  • [x] Create a scheme of the blog creation and modification process
• [x] Fill the titles of the scheme (which are part of the introduction)

[piratax007]

Please update to delete all stuff related to Raspberry pi.

[danilopedraza]

I just did this in a commit tagged with issue #3.