Allow additional markdown options

[NickColley]

I think turning on new features may be too controversial so I'm adding functionality so the user can set their own preferences.

See #169 for why I want to do this.

[NickColley]

Can we do this via the config.yaml file?

[36degrees]

What happens if there are no markdown options specified in the config file? Does this need to be guarded?

[NickColley]

I believe It'll return falsy and the {} will be used.

[36degrees]

Doesn't seem to like the chaining when I try it:

irb(main):004:0> foo = { :tech_docs => { :something => true }}
=> {:tech_docs=>{:something=>true}}
irb(main):005:0> foo[:tech_docs][:markdown].transform_keys(&:to_sym) || {}
Traceback (most recent call last):
        4: from /Users/oliverbyford/.rbenv/versions/2.6.3/bin/irb:23:in `<main>'
        3: from /Users/oliverbyford/.rbenv/versions/2.6.3/bin/irb:23:in `load'
        2: from /Users/oliverbyford/.rbenv/versions/2.6.3/lib/ruby/gems/2.6.0/gems/irb-1.0.0/exe/irb:11:in `<top (required)>'
        1: from (irb):5
NoMethodError (undefined method `transform_keys' for nil:NilClass)

Looks like it works OK with safe navigation (&.) though:

irb(main):004:0> foo = { :tech_docs => { :something => true }}
=> {:tech_docs=>{:something=>true}}
irb(main):006:0> foo[:tech_docs][:markdown]&.transform_keys(&:to_sym) || {}
=> {}
irb(main):007:0> foo = { :tech_docs => { :something => true, :markdown => { :be_awesome => true }}}
=> {:tech_docs=>{:something=>true, :markdown=>{:be_awesome=>true}}}
irb(main):008:0> foo[:tech_docs][:markdown]&.transform_keys(&:to_sym) || {}
=> {:be_awesome=>true}

[NickColley]

this was accidentally added...

[NickColley]

Gonna pause this, write some cards and we can revisit if it makes sense.