update readme

README.md

@@ -4,4 +4,53 @@ rbase
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-Create, read and edit dbf files.
+rbase gem is used to create DBF files.
+
+How to use:
+
+First create a DBF file.
+
+##Creating DBF
+```ruby
+   RBase.create_table 'people' do |t|
+     t.column :name, :string, size: 30
+     t.column :birthdate, :date
+     t.column :active, :boolean
+     t.column :tax, :integer, size: 10, decimal: 2
+   end
+```
+You can provide file path in place of name, eg. `people` can be `tmp/dbfs/people`.
+
+###Options:
+
+  * `:size` - size of the column in characters
+  * `:decimal` - number of decimal positions
+  * `:string` - corresponds to fixed length character column. Column size is limited to 254 (default).
+  * `:date` - date column type
+  * `:boolean` - logical column type
+  * `:integer` - number column type.
+
+  -- Some column types (e.g. :date type) have fixed size that cannot be overridden.
+
+  --Number is stored in human readable form (text representation), so you should specify it's size in characters. Maximum column size is 18 (default).
+
+
+##Adding Records
+
+  The records can be added once the file is created by opening the file using `RBase::Table.open(file_path)` and then calling `create` method and passing a hash. Eg:
+
+```ruby
+    dbf = RBase::Table.open(people)
+    row = {
+            name: "John Doe",
+            birthdate: Date.current,
+            active: 1,
+            tax: 134.23
+          }
+    dbf.create(row)
+    dbf.close
+```
+##Points To Remember
+  - The column name can not be more than 10 characters and should not have spaces.
+  - The column with date type pass the date object not a string or any other.
+  - The gem will generate file in `dbase III` format.