Replace Heroku instructions with Fly.io

Also includes info on how to update the website to reflect event info.

README.md

@@ -19,25 +19,27 @@ Running the app locally
     $ bin/rails server
     $ open http://localhost:3000/
 
-Hiding registration
+Showing registration
 -------------------
 
-Sometimes we create an event, make it live, but don't want people to sign up
-yet. In that case we can set `ENV["HIDE_REGISTRATION]` to `"true"` on Heroku,
-and the registration link won't be shown at all:
+In order to show registration info, you'll need to set the following environment variables:
 
-    heroku config:set HIDE_REGISTRATION=true
+* `EVENT_URL` - URL of the workshop signup
+* `VENUE_NAME` - name of the venue
+* `VENUE_ADDRESS` - one-liner full address of the venue
+* `VENUE_MAP_URL` - an embedded map URL
+* `HIDE_REGISTRATION=true`
 
-Don't forget to un-hide it!
+You can do this by running:
+    fly secrets set EVENT_URL=... VENUE_NAME=... ...
 
-Using real event data
----------------------
+This command will automatically redeploy the app for the new variables to go into effect.
 
-If you'd like to work with actual Eventbrite data, you'll have to set the
-`EVENTBRITE_ACCESS_TOKEN` variable to a real token in your `.env` file.
 
-You can get this via `heroku config:get EVENTBRITE_ACCESS_TOKEN` if you have
-Heroku access or from [Eventbrite App Management] if you have access to the
-RailsBridge Boston Eventbrite account. Otherwise, ask a maintainer for access.
+Sometimes we create an event, make it live, but don't want people to sign up
+yet. In that case we can set `ENV["HIDE_REGISTRATION]` to `"true"` on Heroku,
+and the registration link won't be shown at all:
 
-[Eventbrite App Management]: http://www.eventbrite.com/myaccount/apps/
+    fly secrets set HIDE_REGISTRATION=true
+
+Don't forget to un-hide it!

app/helpers/application_helper.rb

@@ -3,10 +3,6 @@ def signup_form_url
     "//getform.io/f/170d6d2e-01ba-481a-a532-74405f3ed4bc"
   end
 
-  def venue_map_url
-    ENV.fetch("VENUE_MAP_URL", "")
-  end
-
   def data_links
     @data_links ||= YAML.load_file(Rails.root.join("app/data/links.yml"))
   end

app/helpers/events_helper.rb

@@ -4,20 +4,23 @@ def next_event
       venue: venue,
       url: ENV.fetch("EVENT_URL", "")
     )
-    # @next_event ||= Eventbrite::EventFinder.find(ENV.fetch("NEXT_EVENT_ID"))
   end
 
   def next_event_venue
     next_event.venue
   end
 
-  def venue 
+  def venue
     OpenStruct.new(
       name: ENV.fetch("VENUE_NAME", ""),
       address: ENV.fetch("VENUE_ADDRESS", "")
     )
   end
 
+  def venue_map_url
+    ENV.fetch("VENUE_MAP_URL", "")
+  end
+
   def show_registration?
     ENV["HIDE_REGISTRATION"] != "true" && next_event.url.present?
   end