Rename .gemspec

[ohbarye]

Hello, and thanks for the nice gem.

That's a minor point though, this PR renames terms.gemspec to gdpr_rails.gemspec in order to align it with its gem name so that none would confuse the inconsistency.

[coveralls]

Pull Request Test Coverage Report for Build 17

• 0 of 0 (NaN%) changed or added relevant lines in 0 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage increased (+0.3%) to 93.896%

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Files with Coverage Reduction	New Missed Lines	%
test/dummy/app/models/user.rb	1	88.89%
<!--	Total:	1		-->

Totals
Change from base Build 14:	0.3%
Covered Lines:	723
Relevant Lines:	770

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💛 - Coveralls

[michelson]

thanks @ohbarye ❤️ !