the syntax for running the rake task wasn't correct.

Cleaning up the heroku admin command bit to match the form used in Administration-guide.md and clarify the wording a bit.

Removing some of the confusion around what format S3 bucket names and regions should be entered as well as providing an example of an S3 policy that follows best security practices for this sort of thing.

This is a Mastodon with a particular constraint about
what symbols you can post.

Under ## General dependencies:
apt-get needs sudo and install was typed wrongly.

Just launched https://hackertribe.io/, added it to the list.

Add mastodon.land instance

Corrected spelling error for "install"

This guide was pretty out of date and also contained outright errors which were never true. I have updated it.