added visualizations for 1D_laxshocktube to README

Author: RasmitDevkota

examples/1D_laxshocktube/README.md

@@ -1,3 +1,11 @@
 # Lax shock tube problem (1D)
 
-Reference: P. D. Lax, Weak solutions of nonlinear hyperbolic equations and their numerical computation, Communications on pure and applied mathematics 7 (1) (1954) 159–193.
+Reference: P. D. Lax, Weak solutions of nonlinear hyperbolic equations and their numerical computation, Communications on pure and applied mathematics 7 (1) (1954) 159–193.
+
+## Initial Condition
+
+![Initial Condition](initial.png)
+
+## Result
+
+![Result](result.png)