add-apt-repository: add page (#2244)

pages/linux/add-apt-repository.md

@@ -0,0 +1,19 @@
+# add-apt-repository
+
+> Manages apt repository definitions.
+
+- Add a new apt repository:
+
+`add-apt-repository {{repository_spec}}`
+
+- Remove an apt repository:
+
+`add-apt-repository --remove {{repository_spec}}`
+
+- Update the package cache after adding a repository:
+
+`add-apt-repository --update {{repository_spec}}`
+
+- Enable source packages:
+
+`add-apt-repository --enable-source {{repository_spec}}`