Here are the chords of Rainbow by Jessie J. I'm not sure if it's the same chords 
as in the song but it sounds good :)

Verse 1:
Em 
He grew up in the city
Em
Had a lot of money
Em
Sponging off his daddy all the time
Em
He lives in a bubble
Em
Never had to struggle
Em
He's far from the benefit line

Pre-Chorus:
             C        G 
But he feels blue sometimes
       Em                    D     
And he blood bleeds red like mine
             C                    G
The grass is greener on the other side
         Em                  D
What I'm saying is we're all alike

Chorus:
                          Em         C
We're the colours of the rainbow (yeah, yeah)
       G                D
Let's share our pot of gold
                         Em          C
We're the colours of the rainbow (yeah, yeah)
       G                         D
Everybody's on the yellow brick road
                   Em              C
There's enough for you, you, you
                   G              D
There's enough for me, me, me
                         Em          C
We're the colours of the rainbow (yeah, yeah)
                          G          D
We're the colours of the rainbow (yeah, yeah)
Rainbow [x7]

Verse 2:
Em
There's mummy in the ghetto
Em
Gotta work it double
Em
Just to pay the bills and get by
Em
But more power to ya
Em
You're doing what you do-a
Em
Everybody's steady on the grime

Pre-Chorus:
             C         G
But you feel blue sometimes
           Em                    D
And you're blood bleeds red like mine
             C                    G
The grass is greener on the other side
           Em                  D
What I'm saying is we're all alike

Chorus:
                           Em          C
We're the colours of the rainbow (yeah, yeah)
      G                D
Lets share our pot of gold
                          Em            C
We're the colours of the rainbow (yeah, yeah)
      G                         D
Everybody's on the yellow brick road
                    Em               C
There's enough for you, you, you
                    G            D
There's enough for me, me, me
                          Em         C
We're the colours of the rainbow (yeah, yeah)
                          G          D
We're the colours of the rainbow (yeah, yeah)

Bridge:
C            G
Hello, hello
          Em               D
Why does everybody get so mad?
C            G
Yellow, yellow
          Em                         D      
It's the colour for the battle in my head
       C                    G         
I need pink in my life like love in my heart
Em                                    D
Silver in the sky as we rock with the stars
C                 G            Em
We just cant keep fighting anymore
D
No, no, no

Chorus:
                         Em          C
We're the colours of the rainbow (yeah, yeah)
      G                D
Lets share our pot of gold
                          Em            C
We're the colours of the rainbow (yeah, yeah)
      G                         D
Everybody's on the yellow brick road
                    Em               C
There's enough for you, you, you
                    G            D
There's enough for me, me, me
                          Em         C
We're the colours of the rainbow (yeah, yeah)
                          G          D
We're the colours of the rainbow (yeah, yeah)