Add shift-add and shift-delete commands and make commands case-insensitive

[plosslaw]

Resolves #10
Resolves #12
Resolves #15

Test cases will be added in future commits

[codecov-io]

Codecov Report

Merging #42 into master will decrease coverage by 1.49%.
The diff coverage is 0.00%.

@@             Coverage Diff              @@
##             master      #42      +/-   ##
============================================
- Coverage     56.05%   54.56%   -1.50%     
  Complexity      410      410              
============================================
  Files            87       91       +4     
  Lines          1643     1688      +45     
  Branches        183      189       +6     
============================================
  Hits            921      921              
- Misses          684      729      +45     
  Partials         38       38              

Impacted Files	Coverage Δ	Complexity Δ
.../seedu/address/logic/commands/ShiftAddCommand.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...edu/address/logic/commands/ShiftDeleteCommand.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
.../seedu/address/logic/parser/AddressBookParser.java	76.19% <0.00%> (-8.03%)	12.00 <0.00> (ø)
...du/address/logic/parser/ShiftAddCommandParser.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)
...address/logic/parser/ShiftDeleteCommandParser.java	0.00% <0.00%> (ø)	0.00 <0.00> (?)

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[plosslaw]

Currently, the shift-add and shift-edit commands do not support role requirements that uses spaces (e.g. Fry Cook) #44

[WangZijun97]

LGTM! Good fix on the lower case commands. Added a question, but approving as that comment isn't really about the code you are pushing.

[WangZijun97]

Just tested with the current master branch code, 0 does not remove the role from the shift yet, but instead shift-edit removes all roles, then add the ones keyed in. Do we want to have the 0 = remove functionality, or just not allow 0 to be keyed in?

[plosslaw]

I think we'll still go with 0 removing the role

[WangZijun97]

Thanks for helping to update the user guide.