Zero length path eagerload

[amitsuryavanshi]

Fixes #1666

This pull introduces/changes:

• Allows zero length in eager load.

[codecov-commenter]

Codecov Report

Merging #1667 (1a77b92) into master (84f6193) will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #1667      +/-   ##
==========================================
+ Coverage   93.73%   93.76%   +0.02%     
==========================================
  Files         126      127       +1     
  Lines        5684     5707      +23     
==========================================
+ Hits         5328     5351      +23     
  Misses        356      356              

Impacted Files	Coverage Δ
lib/active_graph.rb	98.18% <100.00%> (+0.03%)	⬆️
...tive_graph/node/query/query_proxy_eager_loading.rb	100.00% <100.00%> (ø)
...uery/query_proxy_eager_loading/association_tree.rb	100.00% <100.00%> (ø)
lib/active_graph/string_parsers/relation_parser.rb	100.00% <100.00%> (ø)

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[codeclimate]

Code Climate has analyzed commit 1a77b92 and detected 2 issues on this pull request.

Here's the issue category breakdown:

Category	Count
Complexity	2

View more on Code Climate.

[amitsuryavanshi]

Closing in favour of activegraph-edge gem. This will moved to activegraph-edge gem