Add gitignore Gemfile.lock
Changes Navbar, Addition C2A, Footer Change, Features Edit

I made the nav bar have a fixed position and also changed the wording
of the nav-bar to: Sign-In, Sign-Out, and Sign-Up. Added the call to
action for tablet and desktop, added padding to the bottom of the
footer, and I edited the font size of the features section. I also
resized the jumbotron to 777px