[doc] Fast dev install procedure with Debian 7

[tetraf]

This procedure was tested with Debian 7. You need to replace DB_USER and DB_PASS. Feel free to add this in some README or INSTALL file.

### System dependencies
yes | apt-get install build-essentials git ruby ruby-dev libmysqlclient-dev mysql-server imagemagick
### Rails
gem install -v=2.3.18 rails
### OSV + auth
mkdir -p /srv/http
cd !$
git clone https://github.com/johnmckerrell/OpenStreetView.git openstreetview
cd !$
git clone git://github.com/technoweenie/restful-authentication.git vendor/plugins/restful_authentication
### Ruby dependencies
rake gems:install
gem install mysql
### Db creation
cat << EOF | mysql -h localhost -u root -p
CREATE DATABASE openstreetview_org_development;
GRANT ALL ON openstreetview_org_development.* TO DB_USER@localhost IDENTIFIED BY 'DB_PASS';
EOF
sed -i 's@/tmp/mysql.sock@/var/run/mysqld/mysqld.sock@' config/database.yml
sed -i 's@username: root@username: DB_USER@' config/database.yml
sed -i 's@password:@password: DB_PASS@' config/database.yml
rake db:migrate RAILS_ENV="development"
### Web start
./script/server -e development

There is (at least) an unsolved point: the user is disconnected when he wants to go in "moderate" section (http error 401 from /api/photos/request_more), I don't know if it's a bug or something is missing from the installation.

[alexandre-mbm]

I suggest the README be moved to README.md. Emptied. Then it start with a link to rails.documentation.codyrobbins.com/2.3.18/. After adding the step-by-step above with some explanation.

I can do this in a pull request. But I am in doubt if @johnmckerrell is still accompanied the project. I would have maybe pull requests others.

How to would be with Rake?