Update DG to include Planned Enhancements for tag and insurance command

[yucongkoo]

Closes #296

[codecov]

Codecov Report

Merging #298 (561003a) into master (b7e0340) will not change coverage.
Report is 6 commits behind head on master.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master     #298   +/-   ##
=========================================
  Coverage     71.52%   71.52%           
  Complexity      786      786           
=========================================
  Files           120      120           
  Lines          2732     2732           
  Branches        270      270           
=========================================
  Hits           1954     1954           
  Misses          694      694           
  Partials         84       84           

Files	Coverage Δ
...seedu/address/logic/commands/InsuranceCommand.java	94.64% <ø> (ø)
.../java/seedu/address/logic/commands/TagCommand.java	96.77% <ø> (ø)

[Jweewee]

LGTM