Code cleanup: remove RawData query module

[prioux]

In the early days of CBRAIN we used an ActiveRecord library that wasn't as powerful as the current one.

In order to do some direct column extraction, I created a module that provides these two methods:

result1 = ar_query.raw_first_column(:attribute_name)   # array like [ att, att, att, ... ]
result2 = ar_query.raw_rows([ :atttribute_1, :attribute_2])   # array like [ [att1, att2], [att1, att2], ... ]

These two methods are completely unnecessary anymore, because ActiveRecord has the method pluck() which does almost exactly the same thing.

This issue is about:

1. removing completely the module file BrainPortal/lib/cbrain_extensions/active_record_extensions/relation_extensions/raw_data.rb
2. searching the entire codebase and replacing the calls to raw_first_column() and raw_rows() with pluck() instead.

Some code adjustment might be necessary given the raw_xxx() methods can be invoked without any arguments, unlike pluck().

Checklist over the next few days:

• Adjust CBRAIN codebase
• Adjust CBRAIN plugins ( PR refactor raw_first_column into pluck cbrain-plugins-neuro#294)
• Remove the implementations for raw_rows() and raw_first_column()

[MontrealSergiy]

I think first step 2 should be done, both for core and external plugins, then some time latter step 1.

Otherwise, few important tool will cease working ( including civet and DICOM converters)

[prioux]

Right. I didn't think about the plugins.

So yes, first we do 2. We commit and deploy. Once we know for sure the CBRAIN codebase and the plugins don't use the raw_X() methods anymore, we perform 1.

[prioux]

Just go ahead!

[prioux]

Important!! You missed a few files in the CBRAIN code base:

BrainPortal/lib/tasks/cbrain_plugins.rake
BrainPortal/app/views/tasks/_tasks_display.html.erb
BrainPortal/app/views/userfiles/_quality_control_panel.html.erb
BrainPortal/app/views/users/_users_table.html.erb

For your next pull request, make sure to update these files AND remove the raw_data.rb module

[prioux]

Also, make your PR with master as the base branch (make sure you start with the latest master too)