Add MongoMapper gem and initializer

Signed-off-by: Zeljko <zeljko@zwr.fi>
Add bson_ext to prevent warning

Rake was giving warning, probably from mongomapper initialization,
that this gem , but is needed. Not sure why but here it is.

Signed-off-by: Zeljko <zeljko@zwr.fi>
Add Product scaffold

This adds normal scaffold for Product class, but with Mongo support.
Basically generated using the command from ProductStructure file (see
this commit) and then manually added model file and see (although I was
expecting that only migrations would not be generated).

This actually works pretty much out of the box.

Signed-off-by: Zeljko <zeljko@zwr.fi>
Markdown parsing

Signed-off-by: Zeljko <zeljko@zwr.fi>
Product definition: name and desc required

Signed-off-by: Zeljko <zeljko@zwr.fi>
Rake task db:reset

This task is rather useful, can be called while rails s is running,
but while it exists in ActiveRecord, it is missing in the MongoMapper.

Signed-off-by: Zeljko <zeljko@zwr.fi>
More seeds

Also added catalog as a comment, to think how this should best be
represented. Note that each category can have both products and
subcategories and one product can appear in more than one category.

However, a product still has to have 'main' category, under which
it appears in inventory reports (we do not want double counting
of products).

Since catalog is always loaded complete, never really partial, I am
leaning towards whole catalog being one recurrent object. However,
it should be considered that catalog is also relatively often
modified, so often that it might be needed to make locking (with
Mongo not having transactions, this still means one object is a
benefit).

Signed-off-by: Zeljko <zeljko@zwr.fi>