Double the height of the description textarea

[tcitworld]

Otherwise people think it's a one-line input and don't fill multi-lines (and are afraid to hit backspace to send the form).

[georgehrke]

Hey @Keerthana17,

great that you want to tackle this issue! :)
If you have any questions, please don't hesitate to ask

[zrwitter]

I believe I fixed this with pull request #751.

This is my first real pull request on Github, so any feedback on the process would be appreciated. Thanks!