Added logic to properly set arguments value

[ashkan18]

Problem

We need to properly set the arguments value when creating the query. Currently following code:

Graphlient::Query.new do
  invoices(id: 'test') do
    name
  end
end

results is

{
  invoices(id: test) {
    name
  }
}

Instead of id: "test"

Solution

Before setting the argument check the argument class and properly set it as argument value.

[dblock]

Gemfile.lock should be deleted and added to .gitignore.

[dblock]

Also needs changelog entry, please.

[ashkan18]

Addressed those comments, going to merge 🙌

[dblock]

I cut 0.0.5 with this since it's a major fix.