Updating documentation

[waaberi]

I updated documentation so that people with the requirements.txt problem can fix it. I also modified the page but that isint really important.

[Bryzizzle]

Personally, I had this issue because I used the Deploy to Heroku button instead of setting up a repo manually. This meant that when I cloned the Heroku's repo back to local, I only have an empty repo. Many (including me) would have the intuition to simply add a text file under the name of "server.properties" to the repo, add the configs they want, and then try and push to remote. This created an issue as Heroku can't build the repo (literally only a text file) and reject the push.