Add Create hstore From Two Arrays as a postgres til.

postgres/create-hstore-from-two-arrays.md

@@ -0,0 +1,20 @@
+# Create hstore From Two Arrays
+
+PostgreSQL allows the use of the `hstore` type by enabling the `hstore`
+extension. One way to create an instance of `hstore` data is by passing two
+arrays to the `hstore()` function. The first array is a set of keys and the
+second array is the set of values.
+
+```sql
+> select hstore(array['one','two','three'], array['1','2','3']);
+                hstore
+--------------------------------------
+ "one"=>"1", "two"=>"2", "three"=>"3"
+```
+
+The two arrays must be the same length or an error will occur.
+
+```sql
+> select hstore(array['one','two','three'], array['1','2']);
+ERROR:  arrays must have same bounds
+```