Signed-off-by: Marcin Mikołajczak <me@m4sk.in>

* Remove docker guide and put it in docs repo

* Move tasks to docs repo

* Move requirements to contributing doc

* Move advice about tagged releases to docs repo

* Move local domain and host config to docs repo

* Link to related tech

In current order, docker-compose build results in
ERROR: Couldn't find env file: /a/hopt/mastodon/.env.production

Re-ordered the steps so it doesn't read "Do this, but first, do this
other step"
Added note about keeping the REDIS and DB settings as they are for
Docker use
Add which variables you will NEED to set to make the Mastodon work
Add how to generate the secrets
Add how to connect to your Mastodon
Add a note to read the Production-guide

Add a note to ensure users are using the right version of docker-compose.

This month I traveled to Cambridge, Massachusetts with my friends and attended LibrePlanet 2017. At the talk *Technology for direct actions*, Andrew Seeder pointed out that we often call free software an "alternative" to what exists. But an alternative is something that is mostly similar, and differentiated by preference rather than need. For instance, a trackball is an alternative to a mouse, but a jail is not an alternative to a bedroom. Andrew suggested that we start looking at free software as "solutions" rather than alternatives. So I propose boldly proclaiming that Mastodon is not an alternative to Twitter, but rather a solution to it.

removing web app capability from non-webapp pages

[skip ci]

[ci skip]

[ci skip]

when registering incoming status mentions, add Travis CI file