So, I want to add spells. (involves compendium)

Spells such as those introduced in the princes of the apocalypse 5e campaign. Now my players could do this manually but what about if I wanted to be pro-active and somehow put them into the compendium tab or something similar to a point they only have to drag and drop and have a reference without the book. Suggestions? 

The public Compendium can only contain SRD information.  Some purchases expand the compendium for the purchaser, such as the Monster Manual and Zolo's Guide, but those are only for the person that purchases them, not their players.

dunno what srd means but i'm pretty sure it means I cannot do what I hoped xD

SRD == System Reference Document.  It's all the stuff that can be freely used in Open Gaming License content.  Things that aren't in the SRD cannot be publicly and freely provided. Effectively, it does mean that you can't do what you want with the current state of things.  Steve K. has said that custom compendiums is something he's very interested in adding and I could imagine custom spells being a part of that.  That would allow you to recreate non-SRD content in a private compendium and use it with your players.

brilliant.  Some of the potential updates that's holding back xanthar's guide to everything xp