Update doc.

Author: rubenmromero

README.md

@@ -6,6 +6,29 @@ Script to manage Git projects with multiple submodules and multiple branches per
 
 If you have several initialized submodules in your project, and you handle several branches both in the project as in the related submodules, then you have a Git-Matrix case:
 
+  -------------------------------------
+  | B | B | B | B | | B |
+  | R | R | R | R | | R |
+  | A | A | A | A | | A |
+  | N | N | N | N | ... | N |
+  | C | C | C | C | | C |
+  | H | H | H | H | | H |
+  | 1 | 2 | 3 | 4 | | X |
+ ------------------------|-----|-----|-----|-----|-----|-----|
+ | S U B M O D U L E 1 | | | | | | X |
+ |-----------------------|-----|-----|-----|-----|-----|-----|
+ | S U B M O D U L E 2 | G | | | | I | |
+ |-----------------------|-----|-----|-----|-----|-----|-----|
+ | S U B M O D U L E 3 | | I | | R | | |
+ |-----------------------|-----|-----|-----|-----|-----|-----|
+ | S U B M O D U L E 4 | | | T | | | |
+ |-----------------------|-----|-----|-----|-----|-----|-----|
+ | . . . | | A | | | | |
+ |-----------------------|-----|-----|-----|-----|-----|-----|
+ | S U B M O D U L E Y | M | | | | | |
+ -------------------------------------------------------------
+
+
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   || B R A N C H E S ||
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