module HashRecursiveMerge

h1.merge(h2) #=> {"a" => 100, "b" = >254, "c" => {"c1" => 16, "c3" => 94}}

Simply using Hash#merge would return

h1.rmerge(h2) #=> {"a" => 100, "b" => 254, "c" => {"c1" => 16, "c2" => 14, "c3" => 94}}
h2 = {"b" => 254, "c" => {"c1" => 16, "c3" => 94}}
h1 = {"a" => 100, "b" => 200, "c" => {"c1" => 12, "c2" => 14}}

+other_hash+ value.
includes the same key, the value is merged instead replaced with
If the value of a given key is an Hash and both +other_hash+ abd +hsh
for merging nasted hashes.
Compared with Hash#merge, this method provides a different approch

it merges and returns the values from both arrays.
When both +hsh+ and +other_hash+ contains an entry with the same key,
Compared with Hash#merge!, this method supports nested hashes.

Recursive version of Hash#merge

def rmerge(other_hash)
  r = {}
  merge(other_hash) do |key, oldval, newval|
    r[key] = oldval.class == self.class ? oldval.rmerge(newval) : newval
  end
end