We've known for a while now that the events of "Flashpoint" will change the entire DC TV Universe, and while Grant Gustin has confirmed that The Flash won't remain in that new world forever, that doesn't mean everything will go back to being exactly how it was before (hence why Reverse-Flash is going to be a villain in Legends of Tomorrow). However, Bleeding Cool has today revealed the biggest and most exciting change as this event will apparently be what brings Supergirl permanently to Earth-1.
The character currently hails from another dimension which The Flash inadvertently visited a while back, but "As of the upcoming Flashpoint crossover storyline, Supergirl will now be a part of the main DC TV universe. Only Barry Allen will know that they were once separate… any remaining continuity issues will be handwaved as 'a time traveller did it.'" What this means is that Superman and Supergirl have always been part of The CW-verse, and this makes that upcoming crossover easier!
Are you excited to see Supergirl's world merged with the one Green Arrow and The Flash call home?