Adding function for gfycat

[siikdude 240]

https://www.reddit.com/r/gfycat/comments/2j1t59/phpbb3_gfycat_bbcode/

 

Could this possibly be implemented? 

[Darmuh 1090]

PLS

I WANT GFYCAT THREADS

[Lossy 1968]

gfycat.com/DelayedArtisticGuppy <-- take what ever appears after / and put it inbetween the tags like below. if it ends in .SOMETHING do not add it.

[gfycat]DelayedArtisticGuppy[/gfycat]