Ok so I've played along with all the other tabs, and they don't quite sound right 
to me. So I thought I'd have a go myself. Its quite simple and works fine

Capo 3rd fret, but if your a guy and want to sing along, try without the capo.

Chords:  G/F#  3200033
         D/F#  2002033
         Em7   0220033
         Cadd7 0320033

To keep it simple I'll call them G,D,Em7,C through the song.
Basically your 3rd and 4th fingers stay on the bottom 2 strings at all times. 

Intro
G   D

G
I used to bite my tongue and hold my breath
                   D                   Em7
Scared to rock the boat and make a mess
                           C       G
So I sat quietly, agreed politely

I guess that I forgot I had a choice
                  D                      Em7
I let you push me past the breaking point
                                   C          
I stood for nothing, so I fell for everything


G
You held me down, but I got up (hey!)
                 D            
Already brushing off the dust
Em7
You hear my voice, your hear that sound
                    C
Like thunder, gonna shake the ground
G
You held me down, but I got up
                  D
Get ready cause I had enough
Em7
I see it all, I see it now
          C          G
I got the eye of the tiger, a fighter
                     D
Dancing through the fire
      Em7                               C       G
Cause I am a champion, and you're gonna hear me roar
                       D
Louder, louder than a lion
      Em7                               C       G
Cause I am a champion, and you're gonna hear me roar!


--And follow that pattern all the way through--

[Post-Chorus]
Oh oh oh oh oh oh oh oh (x3)
You’re gonna hear me roar!


Now I’m floating like a butterfly
Stinging like a bee I earned my stripes
I went from zero, to my own hero

[Pre-Chorus]

[Chorus]

[Post-Chorus x2]

[Bridge]
Roar, roar, roar, roar, roar...!

[Chorus]

[Post-Chorus x2]