add Remainder, still need the tests

[mrr00b00t]

Trying to add Remainder transformation, but the tests is needed

[codecov-commenter]

Codecov Report

Merging #27 (d56485d) into master (806be6f) will decrease coverage by 4.09%.
The diff coverage is 0.00%.

❗ Current head d56485d differs from pull request most recent head aa744f6. Consider uploading reports for the commit aa744f6 to get more accurate results

@@            Coverage Diff             @@
##           master      #27      +/-   ##
==========================================
- Coverage   77.50%   73.41%   -4.10%     
==========================================
  Files          12       12              
  Lines         289      331      +42     
==========================================
+ Hits          224      243      +19     
- Misses         65       88      +23     

Impacted Files	Coverage Δ
src/transforms/remainder.jl	0.00% <0.00%> (ø)
src/transforms/closure.jl	86.36% <0.00%> (+86.36%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 806be6f...aa744f6. Read the comment docs.

[mrr00b00t]

I was writing the tests but forgot that the other PR will make changes in tests/transforms.jl, so I decided not to push the tests for the Remainder for now.

[juliohm]

I've finished adjusting small details. Now we need two more adjustments:

1. The column :remainder should be called total_minus_abcdef... where abcdef is just a concatenation of names in the variable names.
2. The two function apply and reapply only differ by the definition of total = func(transform, table, cache). In apply the function computes the total and in reapply the function reads the cache. Can you try to refactor the code that way so that we reduce the amount of code repetition?

[juliohm]

Closing in favor of #28