I just wanted to ask how many words should I write before I can publish it as WiP ? Currently I have written 5k worth of content so should I go ahead and release it or wait until I’ve written more words ?
Because releasing it earlier can help me with feedback from the readers, but I’m not sure if 5k words will be worth reading for them, but this will also show them what kind of story I’m writing.
So help this Taoist out a little 
.
5000 words would be a sizeable chapter in a static story, but it will be over in an eyeblink if there’s any actual branching involved. Especially if you include code in that “5k words” figure.
I’d wait until you have significantly more. I did wait when I first released my WIP, the first public version had 56k words or so. Not because there’s some minimum word count you need to reach, necessarily, but because it’s easier to get people hooked in if the demo has at least one complete scene and preferably a chapter.
Like Omeg says, 5000 words may not feel as much as that when the game is played through. I’d recommend playing through what you have yourself and seeing whether you think it’s a good representation of what you’re doing - do you think it introduces the setting/characters or the kind of decisions the PC will be making well? If you’re not sure it does, it would be a good idea to write another scene or few 
Others have already given you great replies but I would also like to add that I think you also shouldn’t wait too long to publish it because it’s easier to respond to feedback when you don’t have 50k words of code and narrative to go through. I do think 5k is still too short even for a demo though.
I guess I’ll wait until it’s worth reading for readers.