Some things you may need to set up first:
Mapserver: used when showing warped map. Mapserv renamed to mapserv.cgi living in (or linked to) the cgi-bin directory. You'd need to have your own mapserv executable on hand to use for this. FWTOOLS is ok to use for this.
config/deploy.rb for capistrano users, change this as fits. Have a look and see how it works with shared paths, to save mapserver map files and images between deploys.
gdal - needs to be installed, again FWTOOLS good. the path to the gdal executable directory can be added / changed in config/environments/production.rb and/or development.rb if it cannot find it on the PATH.
Some files you will need to put manually there, and capistrano copies across to the correct place, basically enables the code not to have site specific stuff in svn.
config/initializers/mail.rb. put mail.rb into shared/config folder config/environments/production.rb again, into shared/config folder config/database.yml too. see deploy.sample for details
database - standard rails db migrate should do the trick - mysql or sqlite3 should be fine. Change the database.example file to your database.yml
imagemagick is required for paperclip and thumbnail handling.…
For legacy imports from older warper with mapscans you can use the custom rake command
RAILS_ENV=development rake legacy:migrate --trace
Other optional config options put in you environment files
MAX_DIMENSION = 2000 #max dimension width or height for an upload. Otherwise it will get resized to fit this max size MAX_ATTACHMENT_SIZE = 5.megabyte #max upload file size GDAL_MEMORY_LIMIT = 20 # max memory used for gdal_warp, may keep some servers sweet
if you comment these out, then no constraints are used