Rename database client classes

Update our class names to reflect the new file structure introduced in
b700c1bef89a67a64f1040fb6bb03c0320eefe91.

Use the

    module DBShell
      module Client
      end
    end

syntax intead of `DBShell::Client` so that we don't have to define the
`Client` module in a separate file and require it. Otherwise we'd get an
error:

    lib/dbshell/client/sqlite3.rb:1:in `<top (required)>': uninitialized constant DBShell::Client (NameError)

1 files changed, 21 insertions, 17 deletions

diff --git a/lib/dbshell/client/postgres.rb b/lib/dbshell/client/postgres.rb
index 1c1c663..0e33843 100644
--- a/lib/dbshell/client/postgres.rb
+++ b/lib/dbshell/client/postgres.rb
@@ -1,23 +1,27 @@
-class DBShell::PostgresClient
-  EXECUTABLE_NAME = 'psql'
+module DBShell
+  module Client
+    class Postgres
+      EXECUTABLE_NAME = 'psql'
 
-  def self.runshell(db_info)
-    args = self.build_command(db_info)
-    exec(*args)
-  end
+      def self.runshell(db_info)
+        args = self.build_command(db_info)
+        exec(*args)
+      end
 
-  def self.build_command(db_info)
-    args = [EXECUTABLE_NAME]
+      def self.build_command(db_info)
+        args = [EXECUTABLE_NAME]
 
-    host = db_info['host']
-    port = db_info['port']
-    db_name = db_info['database']
-    user = db_info['username']
-    password = db_info['password']
+        host = db_info['host']
+        port = db_info['port']
+        db_name = db_info['database']
+        user = db_info['username']
+        password = db_info['password']
 
-    args.push('-U', user) if user
-    args.push('-h', host) if host
-    args.push('-p', port) if port
-    args.push(db_name)
+        args.push('-U', user) if user
+        args.push('-h', host) if host
+        args.push('-p', port) if port
+        args.push(db_name)
+      end
+    end
   end
 end