jrnl: add page (#2104)

pages/common/jrnl.md

@@ -0,0 +1,23 @@
+# jrnl
+
+> A simple journal application for your command line.
+
+- Insert a new entry with your editor:
+
+`jrnl`
+
+- Quickly insert a new entry:
+
+`jrnl {{today at 3am}}: {{title}}. {{content}}`
+
+- View the last ten entries:
+
+`jrnl -n {{10}}`
+
+- View everything that happened from the start of last year to the start of last march:
+
+`jrnl -from {{"last year"}} -until {{march}}`
+
+- Edit all entries tagged with "texas" and "history":
+
+`jrnl {{@texas}} -and {{@history}} --edit`