You might want to get used to using that, it is very common for english speakers to shorten their sentences by making two words just one using an apostrophe.
EX:
It is = It's
I'd = I would
We are =We're
Slang would be like "aight" when it's really "all right" or "wanna' when it's really "want to", it's either slang or not well written. :P