add readme

Author: hantmac

README.md

@@ -0,0 +1,62 @@
+# Metabase Databend Driver
+
+## Installation
+
+## Configuring
+
+1. Once you've started up Metabase, open http://localhost:3000 , go to add a database and select "Databend".
+2. You'll need to provide the Host/Port,  Database Name, Username and Password.
+
+### Prerequisites
+
+- [Leiningen](https://leiningen.org/)
+
+### Build from source
+
+1. Clone and build metabase dependency jar.
+
+   ```shell
+   git clone https://github.com/metabase/metabase
+   cd metabase
+   clojure -X:deps prep
+   cd modules/drivers
+   clojure -X:deps prep
+   cd ../..
+   clojure -T:build uberjar
+   ```
+
+2. Clone metabase-databend-driver repo
+
+   ```shell
+   cd modules/drivers
+   git clone https://github.com/databendcloud/metabase-databend-driver
+   ```
+
+3. Prepare metabase dependencies
+
+   ```shell
+   cp ../../target/uberjar/metabase.jar metabase-databend-driver/
+   cd metabase-databend-driver
+   mkdir repo
+   mvn deploy:deploy-file -Durl=file:repo -DgroupId=com.databend -DartifactId=metabase-core -Dversion=1.40 -Dpackaging=jar -Dfile=metabase.jar
+   ```
+
+4. Build the jar
+
+   ```shell
+   LEIN_SNAPSHOTS_IN_RELEASE=true DEBUG=1 lein uberjar
+   ```
+
+5. Let's assume we download `metabase.jar` from the [Metabase jar](https://www.metabase.com/docs/latest/operations-guide/running-the-metabase-jar-file.html) to `~/metabase/` and we built the project above. Copy the built jar to the Metabase plugins directly and run Metabase from there!
+
+   ```shell
+   cd ~/metabase/
+   java -jar metabase.jar
+   ```
+
+You should see a message on startup similar to:
+
+```
+2019-05-07 23:27:32 INFO plugins.lazy-loaded-driver :: Registering lazy loading driver :databend...
+2019-05-07 23:27:32 INFO metabase.driver :: Registered driver :databend (parents: #{:sql-jdbc}) 🚚
+```

src/metabase/driver/databend.clj

@@ -184,7 +184,7 @@
                 (merge table-metadata {:fields (set filtered-fields)})))
 
 ; Return a native query that will fetch the current time
-(defmethod driver.common/current-db-time-native-query :firebolt [_]
+(defmethod driver.common/current-db-time-native-query :databend [_]
            "SELECT CAST(CAST(NOW() AS TIMESTAMP) AS VARCHAR(24))")
 
 (defn- to-start-of-year
@@ -279,7 +279,7 @@
            (format "'%s'" (t/format "HH:mm:ss.SSSZZZZZ" t)))
 
 ; Converting OffsetDateTime datatype to SQL-style literal string
-(defmethod unprepare/unprepare-value [:firebolt OffsetDateTime]
+(defmethod unprepare/unprepare-value [:databend OffsetDateTime]
            [_ t]
            (format "'%s'" (u.date/format-sql (t/local-date-time t))))