Update README.md

example :
With the new production plant the company would increase its capacity to meet the expected increase in demand and would improve the use of raw materials and therefore increase the production profitability . (positive- label_0)
Net sales fell by 5 % from the previous accounting period .(negative - label_1 )
The sale price was not disclosed . (neutral -label_2)

README.md

@@ -1,3 +1,4 @@
 0 - positive;
 1 - negative;
-2 - neutral
+2 - neutral 
+