Blog's design

This is the design I have been working. I need the approval of all the members of the team to merge this PR, so reply with "ok" or whatever your want if you really like it, if not, make a comment on what doesn't seems to be right :ear:

You can clone the repo, change to the design branch an execute ```jekyll serve``` and open ```localhost:5247``` on your browsers, or simply check the images in the PR.