added small introduction article for mongodb

added mongodb root vocab

extra/mongodb/driver/driver-docs.factor

@@ -280,9 +280,4 @@ HELP: with-db
 }
 { $description "executes a quotation with the given mdb instance in its context" } ;
 
-ARTICLE: "mongodb.driver" "MongoDB factor driver"
-{ $vocab-link "mongodb.driver" }
-;
-
-ABOUT: "mongodb.driver"
 

extra/mongodb/mongodb-docs.factor

@@ -0,0 +1,27 @@
+USING: assocs help.markup help.syntax kernel quotations ;
+IN: mongodb
+
+ARTICLE: "mongodb" "MongoDB factor integration"
+"The " { $vocab-link "mongodb" } " vocabulary provides two different interfaces to the MongoDB document-oriented database"
+{ $heading "Low-level driver" }
+"The " { $vocab-link "mongodb.driver" } " vocabulary provides a low-level interface to MongoDB."
+{ $unchecked-example
+  "USING: mongodb.driver ;"
+  "\"db\" \"127.0.0.1\" 27017 <mdb>"
+  "[ \"mycollection\" [ H{ { \"name\" \"Alfred\" } { \"age\" 57 } } save ] "
+  "                 [ ageIdx [ \"age\" asc ] key-spec <index-spec> ensure-index ]"
+  "                 [ H{ { \"age\" H{ { \"$gt\" 50 } } } } <query> find-one ] tri ] with-db "
+  "" }
+{ $heading "Highlevel tuple integration" }
+"The " { $vocab-link "mongodb.tuple" } " vocabulary lets you define persistent tuples that can be stored to and retrieved from a MongoDB database"
+{ $unchecked-example
+  "USING: mongodb.driver mongodb.tuple fry ;"
+  "MDBTUPLE: person name age ; "
+  "person \"persons\" { { \"age\" +fieldindex+ } } define-persistent "
+  "\"db\" \"127.0.0.1\" 27017 <mdb>"
+  "person new \"Alfred\" >>name 57 >>age"
+  "'[ _ save-tuple person new 57 >>age select-tuple ] with-db"
+  "" }
+;
+
+ABOUT: "mongodb"

extra/mongodb/mongodb.factor

@@ -0,0 +1,8 @@
+USING: vocabs.loader ;
+
+IN: mongodb
+
+"mongodb.connection" require
+"mongodb.driver" require
+"mongodb.tuple" require
+