Rouges

So I have some player who are playing rouges, they are just about to hit level 5 I am afraid the rouges will become a bit useless because they don’t get an extra attack at level 5 compared to other martials

Rogues don't get an additional attack because they aren't martials. They are skill-monkeys, who can come in clutch in any situation but should not, except under mitigating circumstances, be running face-first into combat. They rely on one powerful attack to do the job, which they have to put a little work into getting to work.

If you want to make the Rogues feel more included, make sure that there are steps leading up to combat, where they can prepare for it. Let them sneak ahead to a good vantage point to attack. But they won't be left behind by fighters - if they wanted to be like fighters, they would have picked fighters!

Don’t forget Rogues have Steady Aim, a bonus action that gives them guaranteed advantage on attacks. With that they’re hitting the majority of the time and getting to add their Sneak Attack which makes up for the fact they only get one attack. I played a 5.5 Rogue all the way to level 20 and rarely felt like I was falling behind other martials in terms of damage plus as Thoruk says I had far more options than them outside of combat with a host of skills and expertises making me far more valuable for skill checks 

Quote from cl0ud_master >>

So I have some player who are playing rouges, they are just about to hit level 5 I am afraid the rouges will become a bit useless because they don’t get an extra attack at level 5 compared to other martials

 They won't Sneak Attack is designed to scale similar to Extra Attack & other martials. So as long as the rogues successfully sneak attack every round they will do as much or more damage than the martials with extra attack. But if you are really worried about it give the rogues a Scimitar of Speed. 

I am afraid the rouges will become a bit useless because they don’t get an extra attack at level ....

I assume your game is 99.7% combat?

Have you thought about creating situations where there are non combat options?   Have the party try to avoid combat.