The GIN index can be used to index arrays; standard PostgreSQL distributions have the GIN operator class for one-dimensional arrays. The GIN index is supported for the following operators:

• The contains operator @>
•  The is contained by operator <@
• The overlapping operator &&
• The equality operators =

The following code shows how to create an Index on color column using GIN function :

CREATE INDEX ON color USING GIN (color);

The index function can be tested by using the following code: 

car_portal=> SET enable_seqscan TO off; -- To force index scan
SET
car_portal=> EXPLAIN SELECT * FROM color WHERE '{red}'::text[] && color;
                                  QUERY PLAN 
------------------------------------------------------------------------------
 Bitmap Heap Scan on color (cost=8.00..12.01 rows=1 width=32)
   Recheck Cond: ('{red}'::text[] && color)
   -> Bitmap Index Scan on color_color_idx (cost=0.00..8.00 rows=1 width=0)
         Index Cond: ('{red}'::text[] && color)
(4 rows)