Add or fix copyright headers

[skalee]

No description provided.

[codecov]

Codecov Report

Merging #121 (8c7e24f) into master (984f08e) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #121   +/-   ##
=======================================
  Coverage   99.46%   99.46%           
=======================================
  Files          24       24           
  Lines         371      371           
=======================================
  Hits          369      369           
  Misses          2        2           

Impacted Files	Coverage Δ
lib/attr_masker/error.rb	100.00% <ø> (ø)
lib/attr_masker/maskers/replacing.rb	100.00% <ø> (ø)
lib/attr_masker/maskers/simple.rb	100.00% <ø> (ø)
lib/attr_masker/model.rb	95.00% <ø> (ø)

---

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 984f08e...dd7a0f2. Read the comment docs.