git-hash-object: add page

pages/common/git-hash-object.md

@@ -0,0 +1,20 @@
+# git hash-object
+
+> Computes the unique hash key of content and optionally creates an object with specified type.
+> More information: <https://git-scm.com/docs/git-hash-object>.
+
+- Compute the object ID without storing it:
+
+`git hash-object {{path/to/file}}`
+
+- Compute the object ID and store it in the Git database:
+
+`git hash-object -w {{path/to/file}}`
+
+- Compute the object ID specifying the object type:
+
+`git hash-object -t {{blob|commit|tag|tree}} {{path/to/file}}`
+
+- Compute the object ID from stdin:
+
+`cat {{path/to/file}} | git hash-object --stdin`