*Learned how to create new hashes and how to test the size of the hash

[65851506]
* learned about acessing hashes with keys via [] and fetch
* with fetch we can generate an exception

[#65851506]
* learned hash elements can be changed
* learned hash elements are unorderd

[#65851506]
* learned hash.keys returns an array of the keys
* learned hash.values returns an array of values

[#65851506]
* learned that when combining hashes (.merge) similar keys overide the values
* learned that one can set the default value for hash (rather than it being nil)

[#65851506]
* learned that when a default value is assigned for a hash, that they all point to the same object
* learned that one can use a {|hash,key| hash[key] = []} to create a new object each time

[#65851506]
Merge pull request #7 from ThomasCGreen/65851506_about_hashes_master

about hashes master

[Delivers #65851506]