Step2: Create function's signature for allowing negative edge sql query

[codeSG]

Function's query:

CREATE OR REPLACE FUNCTION _pgr_bellmanFord(
     TEXT,  -- edges_sql
     TEXT,  -- neg_edges_sql
     ANYARRAY,
     ANYARRAY,
     directed BOOLEAN ,
     only_cost BOOLEAN ,
     ... etc)

Tasks

• Created bellman_ford_neg.sql
• Created _bellman_ford_neg.sql