Add restic support

[nicolaschan]

• Support restic backends

[codecov-commenter]

Codecov Report

Merging #21 (e05eab3) into master (7edc6ec) will not change coverage.
The diff coverage is 100.00%.

@@            Coverage Diff            @@
##            master       #21   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files            1         1           
  Lines          223       263   +40     
=========================================
+ Hits           223       263   +40     

Impacted Files	Coverage Δ
backup.sh	100.00% <100.00%> (ø)

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